One of the "cornerstones" of our botanical-method aquarium practice is the use of substrate. Specifically, substrate materials which can influence- or make it easier to influence- water chemistry in the aquarium, as well as to help foster a "microbiome" of small organisms which will provide ecological diversity for the system.
Substrates, IMHO, are one of the most often-overlooked components of the aquarium. We tend to just add a bag of "_____________" to our tanks and move on to the "more exciting" stuff like rocks and "designer" wood. It's true! Other than planted aquarium enthusiasts, the vast majority of hobbyists seem to have little more than a passing interest in creating and managing a specialized substrate or associated ecology.
A real pity, especially for those of us who are interested in botanical-method aquariums, which replicate natural aquatic habitats where soils and geology play a HUGE role in influencing the environmental parameters of these ecosystems. And in the hobby, we've largely overlooked the benefits and possibilities which specialized substrates can offer.
So I started to experiment with materials to recreate some of the characteristics of wild aquatic habitats which fascinated me. And an obsession was born.
I started playing with substrates mainly because I couldn't find exactly what I was looking for on the market. This is not some indictment of the major substrate manufacturers out there...I LOVE almost all of them and use and happily recommend ones that I like. I'm obsessed with substrates. I think that the companies which produce them are among the coolest of the cool aquatics industry brands. If I wasn't doing this botanical thing with Tannin, I'd probably have started a company that specializes in substrates for aquariums. Seriously.
And the fact is, the major manufacturers need to market products that more than like 8 people are interested in. It's unreasonable to think that they'd devote precious resources to creating a product that would be geared to such a tiny target.
And of course, being one of those 8 people who are geeked-out about weird substrates, I decided that I'd "scratch my own itch" (as we did with the botanical thing..) and formulate and create some of my own. Thus, the NatureBase product line was born!
I realized that the specialized world which we operate in embraces some different ideas, unusual aesthetics, and is fascinated by the function of the environments we strive to replicate. These are important distinctions between what we are doing with substrates at Tannin, and what the rest of the aquarium hobby is doing.
Our NatureBase line is not intended to supersede or completely replace the more commonly available products out there as your "standard" aquarium substrate, because: a) they're more expensive, b) they're not specifically "aesthetic enhancements", c) they are not intended to be planted aquarium substrates, and d) because of their composition, they'll add some turbidity and tint to the aquarium water, at least initially (not everyone could handle THAT!)
So, right there, those factors have significantly segmented our target market...I mean, we're not trying to be the aquarium world's "standard substrate", they weren't formatted to grow aquatic plants, we're not marketing them just for the cool looks, and we can't emphasize enough that they will make your water a bit turbid when first submerged. If you have fishes which dig, or which like to "work" the substrate, you may see a near-continuous turbidity in your aquarium!
Those factors alone will take us out of contention for large segments of the market!
This is important to grasp.
I mean, these substrates are intended to be used in more natural, botanical-style/biotope-inspired aquariums. Our first two releases, "Igapo" and "Varzea", are specific to the creation of a type of "cyclical" terrestrial/aquatic feature. They do exactly what I wanted them to do, and they were specifically intended for use in specialized set ups, like the "Urban Igapo" idea we've been talking about for a long time here, as well as brackish water mangrove environments, etc.
Let's touch on the "aesthetic" part for a minute.
Most of our NatureBase substrates have a significant percentage of clays and sediments in their formulations. These materials have typically been something that aquarists have avoided, because they will cloud the water for a while, and often impart a bit of color. We also have some botanical components in a few of our substrates, because they are intended to be "terrestrial" substrates for a while before being flooded...and when this stuff is first wetted, some of it will float.
And that means that you're going to have to net it out, or let your filter take it out. You simply won't have that "issue" with your typical bag of aquarium sand!
Shit, you're probably just frothing right now, waiting to cloud and dirty up your aquariums with this stuff, huh?
I can't for the life of me figure out why not? ;)
Remember, some of these substrates were formulated for a very specific purpose: To replicate the terrestrial soils which are seasonally inundated in the wild. As such, these products simply won't look or act like your typical aquarium substrate materials!
Scared off completely yet? I hope not.
Why include sediments and clays in our mixes?
Well, for one thing, sediments are an integral part of the natural substrates in the habitats from which our fishes come. So, they're integral to our line. In fact, I suppose you'd best classify NatureBase products as "sedimented substrates."
Think about this: Many of our favorite habitats are forest floors and meadows which undergo periodic flooding cycles in the Amazon, which results in the creation of aquatic habitats for a remarkable diversity of fish species.
Depending on the type of water that flows from the surrounding rivers, the characteristics of the flooded areas may vary. Another important impact is the geology of the substrates over which the rivers and streams pass. This results in differences in the physical-chemical properties of the water.
In the Amazon, areas flooded by rivers of black or clear waters, with acid pH and low sediment load, in addition to being nutritionally poor, are called “igapó."
The flooding often lasts for several weeks or even several months, and the plants and trees need special biochemical adaptations to be able to survive the lack of oxygen around their roots. We've talked about this a lot here over the years.
Forest floor soils in tropical areas are known by soil geologists as "oxisols", and have varying amounts of clay, sediments, minerals like quartz and silica, and various types of organic matter. So it makes sense that when flooded, these "ingredients" will have significant impact on the aquatic environment. This "recipe" is not only compositionally different than typical "off-the-shelf" aquarium sands and substrates- it looks and functions differently, too.
YOU DON'T RINSE THEM BEFORE USE!
You CAN wet them right away; you don't have to do a "wet/dry season" igapo-style tank with them. However, you should be ready for some cloudy water for a week or more! And again, if you have fishes which like to "work" the substrate, it will be a near-constant thing, the degree to which it will be is based on the habits of the fishes you keep.
And that's where a lot of people will metaphorically "leave the room."Turbid, darker water is a guaranteed "freak out" for a super-high high percentage of aquarists.
So, yeah, you'll have to make a mental shift to appreciate a different look and function.
And many hobbyists simply can't handle that. I've been extremely up front with this stuff since the introduction of these substrates, to ward off the, "I added NatureBase to my tank and it looks like a cloudy mess! This stuff is SHIT!" type of emails that inevitably come when people don't read up first before they purchase the stuff. (And trust me- the fact that you're even reading this blog, or listening to this podcast puts you in the tiniest minority of aquarium hobbyists!)
Let's talk a bit about how to "live" with these substrates.
There are a lot of different ways to use these substrates in all sorts of tanks. I mean, if you want some of the benefits and want to geek out and experiment with them, you can use a "sand cap" of whatever conventional substrate you prefer on top, and likely limit the turbidity somewhat, much like the practice of aquarists who employ "dirted" substrates do.
Oh, and the plant thing...
We're asked a LOT if these substrates can grow aquatic plants. Now, although they were intended to facilitate the growth of terrestrial plants, like grasses, the fact is, both our customers and ourselves have seen pretty damn good plant growth in tanks using this stuff!
Our Igapo and Varzea substrates mimic sandy acidic soils that have a low nutrient content. And, as you know, the color and acidity of the floodwater is due to the acidic organic humic substances (tannins) that dissolve into it. The acidity from the water translates into acidic soils, which makes sense, right?
Now, I admit, I am NOT a geologist, and I'm not expert in soil science. I know enough to realize that, in order to replicate the types of habitats I am fascinated with, it required different materials. If you ask me, "Will this fish do well with this materials?" or, "Can I grow "Cryptocoryne in this?", or "Does this make a good substrate for shrimp tanks?" I likely won't have a perfect answer. Sorry.
Periodically, plant enthusiasts will ask me about the "cation exchange capacity" of our substrate. Cation Exchange Capacity (CEC) is the ability of a material to absorb positively-charged nutrient ions. This means the substrate will hold nutrients and make them available for the plant roots, and therefore, plant growth. CEC measures the amount of nutrients, more specifically, positivity changed ions, which a substrate can hold onto/store for future use by aquatic plants.
Thus, a "high CEC" is important to many aquatic plant enthusiasts in their work. While it means that the substrate will hold nutrients and make them available for the plant roots. it doesn't indicate the amount of nutrients the substrate contains.
For reference, scientists measure cation exchange capacity (CEC) in milliequivalents per 100 grams ( meq/100g).
To really get "down and dirty" to analyze substrates scientifically, CEC determinations are often done by a process called "Method 9081A of EPA SW- 846." What the....? CEC extractions are often also analyzed on ICP-OES systems. A rather difficult and pretty expensive process, with equipment and methods that are not something casual hobbyists can easily replicate!
As you might suspect, CEC varies widely among different materials. Sand, for instance, has a CEC less than 1 meq/100 g. Clays tend to be over 30 meq/100 g. Stuff like natural zeolites are around 100 meq/100g! Soils and humus may have CEC up to 250 meq/100g- that's pretty serious!
What nutrients are we talking about here? The most common ones which come into play in the context of CEC are iron, potassium, calcium and magnesium. So, if you're into aquatic plants, high CEC is a good thing!
Of course, this is where the questions arise around the substrates we play with.
It makes sense, right?
Our "Nature Base" substrates do contain materials such as clays and silts, which could arguably be considered "higher CEC" materials, because they're really fine- and because higher surface area generally results in a higher CEC. The more surface area there is, the more potential bonding sites there are for the exchange to take place. Alas, nothing is ever exactly what we hope it should be in this hobby, and clays are often not all that high in their CEC "ratings."
Now, the "Nature Base" substrates are what we like to call “sedimented substrates”, because they are not just sand, or pellets of fired clays, etc. They are a mix of materials, and DO also have some terrestrial soils in the mix, too, which are also likely higher in CEC. And no, we haven't done CEC testing with our substrates...It's likely that in the future, some enthusiastic and curious scientist/hobbyist might just do that, of course!
Promising, from a CEC standpoint, I suppose!
However, again, I must emphasize that they were really created to replicate the substrate materials found in the igapo and varzea habitats of South America, and the overall habitat- more "holistically conceived"-not specifically for plant growth. And, in terrestrial environments like the seasonally-inundated igapo and varzea, nutrients are often lost to volatilization, leaching, erosion, and runoff..
So, it's important for me to make it clear again that these substrates are more representative of a terrestrial soil. Interestingly, the decomposition of detritus and leaves and such in our botanical-method aquariums and "Urban Igapo" displays is likely an even larger source of “stored” nutrients than the CEC of the substrate itself, IMHO. Thus, they will provide a home for beneficial bacteria- breaking down organics and helping to make them more available for plant growth.
Perhaps that's why aquatic plants grow so well in botanical-method aquariums?
Yeah, the stuff DOES grow aquatic and riparian plants and grasses quite well, in our experience! Yet, again- I would not refer to them specifically as "aquatic plant substrates." They're not being released to challenge or replace the well-established aquatic plant soils out there. They're not even intended to be compared to them!
Remember, our "Igapo" and "Varzea" substrates are intended to start out life as "terrestrial" materials, gradually being inundated as we bring on the "wet season." And because of the clay and sediment content of these substrates, you'll see some turbidity or cloudiness in the water. It won't immediately be crystal-clear- just like in Nature. That won't excite a typically planted aquarium lover, for sure.
I can't stress it often enough: With our emphasis on the "wholistic" application of our substrate, our focus is on the "big picture" of these closed aquatic ecosystems.
I'll be the first to tell you that, while I have experimented with many species of plants, inverts, and fishes with these substrates, I can't tell you that every single fish or plant will like them. You'll simply have to experiment!
Well, shit- that's not something that you typically hear an aquarium hobby brand tell you to do with their products every day, huh? Like, I'm not going to make all sorts of generalized statements about everything I think that these products can do. It would be very unhelpful. I'd rather focus on how they perform in the types of systems in which they were intended to work in, and what the possible downsides could be!
The whole point here is that these substrates are perfect for a whole range of applications. They're not "the greatest substrates ever made!" or anything like that. However, they are super useful for replicating the soils of some of our favorite aquatic habitats.
And for doing some of those geeky experiments that we love so much. So, that pretty much covers the "sedimented" substrate thing for now. Let's talk about "alternative" substrates for a bit...
PT.2 : "ALTERNATIVE SUBSTRATES" AND THE "DANGERS" FROM WITHIN?
In my experience, and in the reported experiences from hundreds of aquarists who play with botanical materials breaking down in and on their aquariums' substrates, undetectable nitrate and phosphate levels are typical for this kind of system. When combined with good overall husbandry, it makes for incredibly stable systems.
I've been thinking through further refinements of the "deep botanical bed"/sand substrate relationship. I've been spending a lot of time researching natural aquatic systems and contemplating how we can translate some of this stuff into our closed system aquaria.
Now, I realize, when contemplating really deep aggregations of substrate materials in the aquarium, that we're dealing with closed systems, and the dynamics which affect them are way different than those in Nature, for the most part.
And I realize that experimenting with these unusual approaches to substrates requires not only a sense of adventure, a direction, and some discipline- but a willingness to accept and deal with an entirely different aesthetic than what we know and love. And this also includes pushing into areas and ideas which might make us uncomfortable, not just for the way they look, but for what we are told might be possible risks.
One of the things that many hobbyists ponder when we contemplate creating deep, botanical-heavy substrates, consisting of leaves, sand, and other botanical materials is the possible buildup of hydrogen sulfide, CO2, and other undesirable compounds within the substrate.
Well, it does make sense that if you have a large amount of decomposing material in an aquarium, that some of these compounds are going to accumulate in heavily-"active" substrates. Now, the big "bogeyman" that we all seem to zero in on in our "sum of all fears" scenarios is hydrogen sulfide, which results from bacterial breakdown of organic matter in the total absence of oxygen.
Let's think about this for just a second.
In a botanical bed with materials placed on the substrate, or loosely mixed into the top layers, will it all "pack down" enough to the point where there is a complete lack of oxygen and we develop a significant amount of this reviled compound in our tanks? I just don't think so. I think that we're more likely to see some oxygen in this layer of materials, and I can't help but speculate- and yeah, it IS just speculation- that actual de-nitirifcation (nitrate reduction), which lowers nitrates while producing free nitrogen, might actually be able to occur in a "(deep) botanical" bed.
And it's certainly possible to have denitrification without dangerous hydrogen sulfide levels. As long as even very small amounts of oxygen and nitrates can penetrate into the substrate, this will not become an issue for most systems. I personally have yet to see a botanical-method aquarium where the material has become so "compacted" as to appear to have no circulation whatsoever within the botanical layer.
Now, sure, I'm not a scientist, and I base this on the management of, and close visual inspection of numerous aquariums, as well as the basic chemical tests I've run on my systems under a variety of circumstances. As one who has made it a point to keep my botanical-method aquariums in operation for very extended time frames, I think this is significant. The "bad" side effects we're talking about should manifest over these longer time frames...and they just haven't.
And then there's the question of nitrate.
Although not the terror that ammonia and nitrite are known to be, nitrate accumulation is something a lot of hobbyists are concerned with. As nitrate accumulates, fish will eventually suffer some health issues. Ideally, we strive to keep our nitrate levels no higher than 5-10ppm in our aquariums.
As a reef aquarist, I was always of the "...keep it as close to zero as possible." mindset, until I realized that corals just grow better with the presence of some nitrate! This was especially evident in my large scale coral grow-out raceways.
It seems that 'zero" nitrate is not always the most realistic or achievable target in a heavily-botanical-laden aquarium, although I routinely see undetectable nitrate reading in my tanks. You have a bit more "wiggle room", IMHO, however, before concern over fish health is a factor. Now, when you start creeping towards 50ppm, you're getting closer towards a number that should alert you.
It's not a big "stretch" from 50ppm to more potentially detrimental readings of 75ppm and higher...
And then you get towards the range where health issues could manifest themselves in your fishes. Now, many fishes will not show any symptoms of nitrate poisoning until the nitrate level reaches 100 ppm or more. However, studies have shown that long-term exposure to moderate concentrations of nitrate stresses fishes, making them more susceptible to disease, affecting their growth rates, and inhibiting spawning in many species.
At those really high nitrate levels, fishes will become noticeably lethargic, and may have other health issues that are obvious upon visual inspection, such as open sores or reddish patches on their skin. And then, you'd have those "mysterious deaths" and the sudden death (essentially from shock) of newly-added fishes to the aquarium, because they're not acclimated to the higher nitrate concentrations.
Okay, that's scary stuff. However, high nitrate concentrations are not only manageable- they're something that's completely avoidable in our aquairums.
Quite honestly, even in the most heavily-botanical-laden systems I've played with, I have personally never seen a higher nitrate reading than around 5ppm. Often, as I mentioned above, they're undetectibIe on hobby-level test kits. I attribute this to common sense stuff: Good quality source water (RO/DI), careful stocking, feeding, good circulation, not disturbing the substrate, and consistent basic aquarium husbandry practices (water exchanges, filter maintenance, etc.).
Now, that's just me.
I'm no scientist, certainly not a chemist, but I have a basic understanding of maintaining a healthy nitrogen cycle in the aquarium. And I am habitual-perhaps even obsessive- about consistent maintenance. Water exchanges are not a "when I get around to it" thing in my aquarium management "playbook"- they're "baked in" to my practice.
So yeah, although nitrate is something to be aware of in botanical-method aquariums, it's simply not an ominous cloud hanging over our success.
Relatively shallow sand or substrate beds seem to be optimal for denitrification, and many of us employ them for the aesthetics as well. Light "stirring" of the top layers, if you're concerned about any potential "dead spots" is something that is permissible, IMHO. Any debris stirred up can easily be removed mechanically by filtration, as mentioned above.
But that's it.
Of course, as we already discussed, you don't have to go crazy siphoning the shit (literally!) out of your sand every week, essentially decimating populations of beneficial microscopic infauna -or interfering with their function- in the process.
What I am starting to feel more and more confident about is postulating that some form of denitrification occurs in a system with a layer of leaves and botanicals as a major component of the tank.
Now, I know, I have little rigorous scientific information to back up my theory, other than anecdotal observations and even some assumptions. However, there is always an example to look at- Nature.
Of course, Nature and aquariums differ, one being a closed system and the other being "open." However, they both are beholden to the same laws, aren't they? And I believe that the function of the captive leaf litter bed and the wild litter beds are remarkably similar to a great extent.
The thing that fascinates me is that, in Nature, leaf litter beds perform a similar function; that is, fostering biodiversity, nutrient export, and yes- denitrification. Let's take a little look at a some information I gleaned from the study of a natural leaf litter bed for some insights.
In a slow-flowing wild Amazonian stream with a very deep leaf litter bed, observations were made which are of some interest to us. First off, oxygen saturation was 6.7 3 mg/L (about 85% of saturation), conductivity was 13.8 microsemions, and pH was 3.5.
Some of these parameters (specifically the very low pH) are likely difficult to obtain and maintain in the aquarium, but the interesting thing is that these parameters were stable throughout a months-long investigation.
Oxygen saturation was surpassingly low, given the fact that there was some water movement and turbulence when the study was conducted. The researchers postulated that the reduction in oxygen saturation presumably reflects respiratory consumption by the organisms residing in the litter, as well as low photosynthetic generation (which makes sense, because there is no real algae or plant growth in the litter beds).
And of course, such numbers are consistent with the presence of a lot of life in the litter beds.
Microscopic investigation confirmed that the leaf litter was heavily populated with fungi and other microfauna. There was also a significant amount of fish life. Interestingly, the fish population was largely found in the top 12"/30cm of the litter bed, which was estimated to be about 18"/45cm deep. The food web in this type of habitat is comprised largely of fungal and bacterial growth which occurs in the decomposing leaf litter.
Okay, I"m throwing a lot of information here, and doing what I hope is a slightly better-than-mediocre attempt at tying it all together. The principal assertions I'm making are that, in the wild, the leaf litter bed is a very productive place, and has a significant impact on its surroundings, and that it's increasingly obvious to me that many of the same functions occur in an aquarium utilizing leaf litter and botanicals.
"Enriching" a substrate with botanicals, or composing an entire substrate of botanicals and leaves is a very interesting and compelling subject for investigation by hobbyists.
So, three areas of potential investigation for us:
*Use of botanicals and leaves to comprise a "bed" for bacterial growth and denitrification.
*Understanding the chemical/physical impact of the botanical "bed" on an aquarium. (ie, pH, conductivity, etc.)
*Utilization of a botanical bed to create a supplemental food source for the resident fishes.
We've also touched on the idea of a leaf litter/botanical bed as "nursery" for fry, something more and more hobbyists/breeders are confirming is a logical "go-to" thing for them.
Interesting semi-anecdotal observations from my friends in the know suggest that the biofilms for decaying leaves form a valuable secondary food for the fry of fishes such as Discus, Uaru, (after they’re done feeding on their parent’s exuded slime coat) and even Loricariid catfishes. And I've seen juvenile fishes of a variety of species "appear" from my botanical-rich aquariums over the years, fat and happy, apparently deriving some nutrition from the fungi, bacteria, and small crustaceans which live in, on, and among the leaf litter bed.
My own experience with creating leaf-litter-bed-focused aquariums has proven that supplemental food production for the resident fishes is a real "thing" that we need to consider. It's a valid and very exciting approach to creating a functional closed aquatic ecosystem.
We talk about the concept of "substrate enhancement" or "enrichment" a lot in the context of aquatic botanicals (we tend to use the two terms interchangeably).
Again, we're not talking about "enrichment" in the same context as say, planted aquarium guys, with materials put into the substrate specifically for the benefit of plants. However, the addition of botanical and other materials CAN create a sort of organic "mulch" which benefits many aquatic plants!
Rather, "enrichment" in our context refers to the addition of botanical materials for creating a more natural-appearing, natural-functioning substrate- one which provides a haven for microbial life, as well as for small crustaceans, biofilms, and even algae, to serve as a foraging area for our fishes and invertebrates.
We've found over the years of playing with botanical materials that substrates can be really dynamic places, and benefit from the addition of leaves and other materials. For many years, substrates in aquarium were really just sands and gravels. With the popularity of planted aquariums, new materials, like soils and mineral additives, entered into the fray.
With the botanical-method aquarium starting to gain in popularity, now you're seeing all sorts of materials added on and in the substrate...for different reasons of course.
I think the big takeaway is that we should not be afraid to experiment with the idea of mixing various botanical materials into our substrates, particularly if we continue to embrace solid aquarium husbandry practices.
In my opinion, richer, botanically-enhanced substrate provides greater biological diversity and stability for the closed system aquarium.
Is it for everyone?
Not for those not willing to experiment and be diligent about monitoring and maintaining water quality. Not for those who are superficially interested, or just in it for the unique aesthetics it affords.
However, for those of you who are adventurous, experimental, diligent, and otherwise engaged with managing and observing your aquariums, I think it offers amazing possibilities. Not only will you gain some fascinating insights and the benefits of "on-board" nutrient export/environmental "enrichment"- you will also get the aesthetics of a more natural-looking substrate as well.
Like so many things we do in our niche, the "weird" alternative and botanical-enriched substrate approaches are fascinating, dynamic, and potentially ground-breaking for the aquarium hobby. For the adventurous, diligent, and observant aquarist, they present numerous opportunities to learn, explore, and create amazing, function-first aquatic ecosystems.
Stay creative. Stay observant. Stay diligent. Stay thoughtful...
And Stay Wet.
It goes without saying that the single most important component of our aquariums is also the most obvious...water! As the literal bearer of life and the environment in which our fishes, plants, and other organisms thrive, it's fundamental. it's the reason we're drawn to fishes, not gerbils, Tarantula, or Mice- or whatever other pets people keep!
Yeah, we're into water!
And I dear say that we take it for granted a bit.
Now, sure, some hobbyist rightfully place the importance of good quality, properly-conditioned water at the very top of their "want list" of "Stuff" required for successful aquariums. These are often fish breeders and very serious hobbyists, who understand the fundamental importance of good water for their work.
Some of the most common questions we receive lately are "How much _______ do I need to get my water to look like________?" or "How much_______ is needed to lower the pH in my tank?" Or, "How much do I need to get a good amount of humic substances and tannins into my aquarium?"
I usually respond with a simple, "I don't know."
These are all really good questions. Logical. Important. I kind of feel like many hobbyists are looking for a plug-and-play "formula" or "recipe" for how to accomplish certain water-conditioning tasks.
I totally get that. But the reality is...there IS no "recipe" for how to do this stuff.
And it sucks, I know.
"Why, Scott? I read that you can just add some of this blackwater extract that you can buy online, and maybe add some catappa leaves, and..."
Stop. STOP. Please, we're just making this painful.
Simply adding leaves or bottled extracts to your tap water isn't going to result in "Instant Amazon" or whatever. There are numerous complexities and nuances which contribute to these habitats that to simply recommend adding "X" to your water isn't the whole story.
There are so many variables in the equation that it's almost impossible to give a definitive answer. And yeah, us guys in the botanical biz haven't really helped the situation. Over the years, vendors who sold catappa leaves, for example, would recommend starting amounts ("three leaves per 15 liters of water" or whatever...) of botanical materials to use in aquariums.
I mean, we've sort of done it, too...And, although our recommended "dosage" of leaves was given for different reasons (to avoid adding too much material to your tank too quickly), the idea of a "recipe" in general is kind of delusional, IMHO.
Now, this was all well and good, but it's based on....what? I mean, is this based on how many leaves of _______ size that a typical hobbyist with a 10-gallon aquarium needs to get the water "looking brown?" Or to lower tap water with a starting pH of 7.4 and a KH of ___ to pH of 6.9? Or to impart "x" ppm of tannins or humic substances into this given quantity of water?
See? Add to this story the fact that you really can't soften water and make it more "malleable" by using botanicals or extracts alone, and you've got a good case for confusion! It's just not that simple.
Maybe we can gain a bit of understanding- or at least, an appreciation for the dynamics of this process, by looking once again to Nature.
Have you very thought about how water reaches all of the wild aquatic systems of the world? I mean, it's got to get there some way, right? So, how does it reach the ponds, lakes, streams, and rivers and forest floors of the world?
Well, some simply falls into the body of water directly from the sky, and that's that. Some is a result of other overflowing streams and rivers (like, ya' know- those flooded Igapo forests we talk about!). Inputs of precipitation falling over the area of an aquatic habitat are transferred to the habitat via a number of different pathways.
It's surprisingly complicated.
There's like a whole field of science devoted to studying this process! It's called Hydrology, and it's incredibly interesting...As fish geeks, we're probably already acquainted with this field of study, at least tangentially!
So, water comes from a variety of sources, reaching a myriad of ecological niches. However, not all of the water has such an easy journey on its way into our favorite aquatic habitat!
Even in the case of rainwater, some of it simply lands on tree leaves in the surrounding area and evaporates. This is a process scientists call "interception", and accounts for the fact that not all water makes it to the ground. Water that does reach the ground enters the soil through a process called infiltration. slowly percolating down to soil areas known as the "saturated zone"- and as you'd imagine, this is where the fun really begins! (to a soil geologist, at least!)
The soil properties control the infiltration capacity; these include things like soil permeability, the presence of vegetation and plant roots, and how much water is already in the soil. Through what is known as "ground water flow", ultimately, the water finds it way into our favorite aquatic habitats. It's important to note that soil texture ( the relative proportion of sand, silt and clay particles within the mix) affects infiltration rates.
Sandy soils like the "podzols", common to forested areas of South America that we've talked about have higher permeability than some clay-based soils. In some really arid areas a "crust" can form on the soil surface, decreasing the permeability. And of course, the thickness of the soil directly affects how much water the soil can actually absorb.
And, in many cases, the substrate composition and its relationship with water has direct impact on the life forms which inhabit these aquatic systems. In the case of some habitats, like vernal pools, which are filled with water seasonally, the substrate is of critical importance to the aquatic life forms which reside there.
Yeah, soils and geology are perhaps the primary driver of water composition in Nature.
Let's talk more about "blackwater."
In a blackwater environment, the color is a visual indicator of an influx of dissolved materials that contribute to the "richness" of the environment. Indeed, a blackwater environment is typically described as an aquatic system in which vegetation decays, creating tannins that leach into the water, making a transparent, acidic water that is darkly stained, resembling tea.
But, that's not the whole story, really.
It’s important to really try to understand the most simple of questions- like, what exactly is “blackwater”, anyways?
A scientist or ecologist will tell you that blackwater is created by draining from older rocks and soils (in Amazonia, look up the “Guyana Shield”), which result in dissolved fulvic and humic substances, present small amounts of suspended sediment, and characterized by lower pH (4.0 to 6.0) and dissolved elements, yet higher SiO2 contents. Magnesium, Sodium, Potassium, and Calcium concentrations are typically very low in blackwater. Electrical conductivity (ORP) is also lower than in so-called "whitewater" habitats.
Tannins are also imparted into the water by leaves and other botanical materials which accumulate in these habitats.
The action of water upon fallen leaves and other botanical-derived materials leaches various compounds out of them, creating the deep tint that many of us are so familiar with. Indeed, this "leaching" process is analogous to boiling leaves for tea. The leached compounds are both organic and inorganic, and include things like tannin, carbohydrates, organic acids, pectic compounds, minerals, growth hormones, alkaloids, and phenolic compounds.
Most of the of the extractable substances in the surface litter layer are humic acids, typically coming from decaying plant material. Scientists have concluded that greater input of plant litter leads to greater input of humic substances into ground water.
In other words, those leaves that accumulate on the substrate are putting out significant amounts of humic acids, as we've talked about previously! And although humic substances, like fulvic acid, are found in both blackwater and clear water habitats, the organic detritus (you know, from leaves and such) in blackwater contains more extractable fulvic acid than in clearwater habitats, as one might suspect!
The Rio Negro, for example, contains mostly humic acids, indicating that suspended sediment selectively adsorbs humic acids from black water. The low concentration of suspended sediments in rivers like the Rio Negro is one of the main reasons why high concentrations of humic acids are maintained. With little to no suspended sediment, there is no "adsorbent surface" (other than the substrate of the river, upon which these acids can be taken hold of (adsorb).
When you think about it, all of this this kind of contributes to why blackwater has the color that it does, too. Blackwater in the Amazon basin is colored reddish-brown. Why? Well, it has those organic compounds dissolved in it, of course. And most light absorbtion is in the blue region of the spectrum, and the water is almost transparent to red light, which explains the red coloration of the water!
And many of those organic compounds come from the surrounding land, as touched on above...
In summary, natural "blackwaters" typically arise from highly leached (tropical) environments where most of the soluble elements in the surrounding rocks and soils are rapidly removed by heavy rainfall. Materials such as soils are the primary influence on the composition of blackwater.
Leaves and other materials contribute to the process and appearance in Nature, but are NOT the primary “drivers” of its creation and composition.
So, right from the start, it’s evident that natural blackwater is “all about the soils…” Yeah, I'll repeat it again: It’s more a product of geology than just about anything else.
More confusing, recent studies have found that most of the acidity in black waters can be attributed to dissolved organic substances, and not to dissolved carbonic acid. In other words, organic acids from compounds found in soil and decomposing plant material, as opposed to inorganic sources. Blackwaters are almost always characterized by high percentages of organic acids.
Despite the appearance, as a general rule, blackwater rivers are lower in nutrients than clear rivers. Wouldn't it be interesting, when contemplating more natural biotope/biotype aquariums, to study and take into consideration the surrounding geology and physical characteristics of the habitat? Too recreate the habitat based on the soil or geological composition of the surrounding terrestrial environment?
As we know now, the influence of factors like soil, and the presence of terrestrial materials like seed pods, leaves, and branches play a huge role in the chemical composition and appearance-of the water. It's really no different in the aquarium, right?
Like so many things in nature, the complexity of blackwater habitats is more than what meets the eye. Chemically, biologically, and ecologically, blackwater habitats are a weave of interdependencies- with soil, water, and surrounding forest all functioning together to influence the lives of the fishes which reside within them. No single factor could provide all of the necessary components for fish populations to thrive.
To damage or destroy any one of them could spell disaster for the fishes- and the ecosystem which supports them. It is therefore incumbent upon us to understand, protect, and cherish these precious habitats, for the benefit of future generations.
And with regards to our aquarium work?
Although there may even be breakthroughs in terms of blackwater extracts and additives coming to market, there are still a lot of questions that would have to be answered before we could simply state that "X" drops per gallon of such an such a formula would yield a specific outcome. This reminds me of the reef aquarium world more an more, lol.
So, if I've made any "argument" here, it's that this stuff is every bit as much of an "art"- in terms of aquarium keeping- as it is a "science." We will, at least for the foreseeable future, have to use the data we have available and formulate a best guess as to how much of what can give us some of the impacts we are interested in for our aquariums.
We simply can't authoritatively make blanket statements like, "You need to use "X" catappa leaves per gallon in order to recreate Rio Negro-like conditions in your aquarium!" We can't simply state that you can throw in some podzolic soil and achieve blackwater, either. There are many factors in play, as we've discussed here, right?
Marketing hyperbole aside, we really are sort of...guessing.
And that's certainly nothing to be discouraged about!
We, as a community, are getting deeper into the functional aspects of blackwater, botanical-style aquariums than ever before. More light is being shed on what's going on in both our aquariums and in the natural habitats we desire to replicate. We are learning more every day about how the presence of tannins and humic substances in our aquariums is affecting the health, longevity, and spawning behaviors of our blackwater fishes.
We're learning about the challenges and realities of managing blackwater systems over the long term- understanding the good, the bad, and the dangerous possibilities that are present when we experiment with these ideas.
There is much, much more work to be done..And a lot of talented hobbyists like yourself are out there on the front lines every day, contributing to the body of knowledge that will benefit the hobby for generations!
Stay persistent. Stay bold. Stay open-minded. Stay curious. Stay disciplined...
And Stay Wet.
Today. I'm sort of taking a contrary stance to what you might typically see in aquarium blogs. Okay, what else is new, right?
My position is this: The aquarium hobby, while not "difficult", is not super easy, either. And quite honest, it shouldn't be super easy. And we shouldn't be 'dumbing it down' so much.
Uh-ohh. Controversy time.
Well, before you go and label me a jackass and pelt me with "Hakkai Stones", think about it: We are creating and managing the entire environment for specialized living creatures. Unlike a dog or cat, which (at the risk of over simplifying things) just needs food and a place to sleep to survive, fishes require a place to live, the proper aquatic environment, including heat, nutrient export, food, oxygenation, and light. We also are responsible for creating a compatible community of animals, understanding the dynamics of the nitrogen cycle, quarantine, acclimation, disease identification and treatment, and a lot more.
Sure, having to master all of these that I things listed out makes it sound like we're freaking genius-level people to be successful. We don't have to be, of course (I mean, look at some of the clowns who are YouTube “influencers” and the drivel they generate...😂)- but we do have to understand and be able to execute successfully on a number of fronts in order not to kill our fishes immediately, don't we?
Now, a little bit of props to the fishes themselves! I mean, they're subjected to a lot of shit before they get to us, right? Wild fishes, especially, undergo a real trial just to get to us: Collection, sorting by the fishers, a few days at a exporter's facility, a flight from their home country, a stint at a wholesaler, then on to the LFS, and finally to you. All the while, adapting to varying conditions, crowding, and little, if any food. When you think about it, it's hard to believe that they survive at all!
Back to our gig.
As hobbyists, we're morally obligated to have at least a rudimentary understanding of the requirements which our fishes need to survive and thrive. And, unfortunately, in today's "Insta-fast" "Everyone can go from zero to hero in three days" social-media-driven hobby, many hobbyists simply don't have that. In fact, if you asked 10 hobbyists some of the most basic aquarium-related questions, such as how the nitrogen cycle works, or what pH means, I'll wager that you'd likely get 3-4 hobbyists who couldn't articulate anything about these topics.
However, if you ask them about the best aquascaping rock, trendy approach, or stupidly-named wood type, I'll bet they'll be able to tell you everything you'd care to know.
That's indicative of a problem. When we accept this level of mediocrity, we're making ignorance of the art and science of aquarium keeping cool.
We're better than this.
We as hobbyists need to educate ourselves before we leap. Now, at this point, there are likely a few readers/listeners who will be like, "Damn, Captain Buzzkill, you're making it like you have to be a freaking marine biologist to be able to keep tropical fish! WTF?"
No, I'm not. And pointing out reality doesn't make me a complete asshole. Well, sort of an asshole- but not a complete one! 😆
Seriously, though, there is something really wrong when we have hobbyists trying all sorts of crazy expensive and exotic hobby ideas and equipment, when their fundamental understanding of the aquarium hobby is essentially inadequate.
Like, we've created a generation of hobbyists who want to run before they can walk. They're always looking for "hacks" and shortcuts for "making things easier." And when they fail- they have no way to understand why. And they often quit the hobby as a result. I've seen this dozens of times during my hobby "career." And we- the industry, creators, and communicators of the aquariums hobby- are responsible for this.
Now look, I'm all for making things easier, but NOT for dumbing down stuff. It shouldn't be like having to take board examinations in order to keep a fish tank, and setting up and caring for a tank shouldn't always be onerous- but you should at least try to have a working knowledge of a bunch of fundamental topics before you plunk down your cash and put fishes' lives on the line, right? And you should want to. And we as hobbyists should be interested in learning and acquiring the basic skills necessary to assure a good start in the hobby. We don't need to make this a task; we just need to do a little basic research first.
This is where the local fish store can excel.
The "mentoring" you can receive from a quality fish store is one of the best first exposures you can have to the art and science of aquairum keeping. As long as they don't take a purely sales-oriented approach to things (and most don't, despite the popular, persistent hobby mythology of the buffoonish, ignorant, and predatory LFS personnel that have been the stuff of online lore for decades now). Most LFS staff are uber hobbyists, obsessed with aquariums and fishes, and have a vested interest in seeing their customers succeed.
For those who need to get their "education" online, there are a lot of good resources. I don't need to rehash that. However, despite its popularity and search ability, YouTube isn't always the best source. There ARE a lot of great channels out there, but there is also a disproportionately high number of outright garbage, too. Channels in which the "creator" seems to have absolutely no clue about the topic he/she is authoritatively spewing. In our own sector alone, I've seen this several times. It's vomit inducing.
And a lot of the stuff out there- even "sponsored content"- is about drivel...doing a certain scape with this cool rock, or how to arrange wood so that your tank looks like everyone else's', or something equally as vapid. There is proportionately little produced about fundamental hobby stuff.
We can't run from some of the science stuff...I mean, we are ALL at the mercy of the nitrogen cycle, for example, and we need to have at least a basic understanding of how it works and what the implications are for our aquarium work. It's actually really important!
When I co-owned a coral propagation/import business, a scarily high percentage of the questions from customers were frighteningly basic- like stuff you should know before you ever even buy any aquarium, let alone set up a reef tank.
Back in those days, I literally received calls from hobbyists who didn't have the most rudimentary understanding of the needs of corals, let alone, the nitrogen cycle- yet they spent tens of thousands of dollars outfitting their reef tank with the latest gear, and buying the latest "designer frags."
it was head-scratching, to say the least. It was downright discouraging on some days.
It's not just limited to the reef world, of course. It’s all over the hobby.
And, it's our fault as an industry, too.
We seem to sell prepackaged "solutions" for everything. Another piece of gear, another additive..."That'll solve your problems!" We seem to be happier just selling people a product that we hope will solve their problems. Laughably, I've seen soem vendors/manufacturers trot out the pathetic line about their product making things easier so you could "enjoy the hobby more!" Like, WTF? Isn't feeding your fishes, doing water exchanges, and just managing the tank part of what makes it enjoyable, too? Or is the only enjoyable part of the hobby humble-bragging on The 'Gram about our latest aquascape?
How about we educate people on the basics and beyond? The good, the bad, and the shitty? That will make the use of your product a lot more logical. Yet, I know- it takes time. It's more difficult to educate people on the underlying problem...the reason why people would need your product in the first place. It's much easier to just tell them what to buy and that's that. It sells stuff faster. But it doesn't build a long-term hobbyist. That's why we at Tannin have article after article on the most basic, and even arcane aspects of playing with blackwater/botanical-style aquariums on our site.
Because I believe that hobbyists have to be armed with the most fundamental knowledge of our craft in order to succeed. I'm not going to just show pretty pics of cool 'scapes and sell seed pods and leaves that way. That's how I'm going to do my part to address the hobby dropout thing. My friends James of Blackwater UK and Ben of Betta Botanicals, two vendors as geeked out as I am about this stuff, are on the same page as me. We're determined to show hobbyists that the process- the whole thing- is as much fun as just looking at the number of likes your tank pics get on your fave social media channel.
It's a wider hobby "cultural problem", too. We're lazy. A lot of us want instant gratification and simply don't want to take the time to dig through information- even if it's out there in abundance. They want it easier. Faster. More concise.
And yes-I know. Everyone is "busy", etc. Yet, why have a hobby in the first place if you don't want to spend time playing with it and educating yourself about it? People can't be lazy. They have to learn the underlying, fundamental stuff. They need to read, watch, discuss, observe. A personal example again? I get numerous emails asking me how to prepare botanicals- even after we spent hundreds and hundreds of dollars on producing a customized infographic card that goes in every order, and years writing dozens of articles on this very topic.
Some people seem so unwilling to do the most basic research! What a shame. I mean, Google is one of the greatest inventions in the history of humanity, making information about virtually any topic imaginable available anywhere, any time, to anyone. Easily.
Yet, many figure the "hack" is just to ask someone and expect them to give concise answers on how to do everything, instead of taking the extra time to educate themselves a bit before just mailing it in and prodding someone else for the answer. Yeah, we've somehow decided that a DM to someone for a “quick answer” is a better way to acquire knowledge than typing in the keywords, like "what is the nitrogen cycle?" and learning it once and for all.
Obviously, as an industry guy and writer- I'm always going to help those with questions when I can...But I also need to encourage self-research, too. I still need to do better at disseminating information. We all do.
There's blame enough to go around. And to newbies and others in the hobby-my plea to you:
Don't be freaking lazy. The resources are there.
We just have to keep directing people towards them. And people need to use them. And we have to emphasize the fundamentals of the hobby. Not just the cool creative stuff. Sure, not everyone is great at conveying technical concepts to people in an easy-to-understand manner. However, we can try, Because, when no one is doing that, we end up with 14,000 channels on how to "scape a blackwater aquairum" and not a single one explaining what the hell blackwater is, and how to manage the ecology of a blackwater system.
That's a problem, IMHO.
Everyone wants to do the "fun" stuff, hype their sponsors' products, and get all of that recognition. Yet, without discussing the less sexy fundamentals, the "fun stuff" just becomes a waste of precious animal lives and lots of money. People get frustrated and quit the hobby. When I see the words "paid partnership" under an Instagram post lately, I almost reflexively (and often correctly, I'm afraid) assume that it's usually drivel. Because most of the creators- and the brands who sponsor them- have accepted a level of superficiality as the norm. And that's really sad. These people are too talented to waste their followers' precious attention- and their sponsor's money- by producing such mindless fluff.
The "creative" and "trendy" is valued over the substance, even by brands. And the irony is that doing a little more substance in a creative manner is what will sell more product and build a stronger brand in the long run. Yet, it's easier to just pay some "creator" do a fun little video with a bit of hip-hop music, the appropriate sponsor hashtags, and consider it a job well done.
I call bullshit on that.
Brands need to stop paying these "creators" for this garbage.
You can still be creative and edgy and cool while conveying complex or arcane topics... Hell, we do it all the time here (so modest, right?).
Yes, even in the social media "Insta-hype" world we're in, there is room for improvement. I've hit this hard before...we all show too much "finished product" with killer aquascapes and such, and not enough of the less sexy, although way more important process...
There is an easy fix for that one. Just share the process.
Discuss the fundamentals of what you do.
When hobbyists realize it's not just "1-2-3 AWESOME!"- and that there is a little work, and occasional setbacks and struggle involved, expectations are set which assure people go in with their eyes wide open...and stay in. Expectation management via education. And there is a certain responsibility that we as hobbyists take on when keeping live fishes; this needs to be emphasized. And guess what, fellow aquarium brands? They'll still buy your product. In fact, they'll probably be more likely to, because they will have a fundamental understanding for why they need it.
No. The aquarium hobby isn't that easy.
But it's not ridiculously hard, either.
We have a responsibility as hobbyists to keep these precious creatures alive and happy. And we as hobby and industry people have an obligation to tell it like it is. To touch on fundamentals. To explain things. To convey that, while not overly complex, some the underlying information that you need to know to be successful in the hobby is vital. Even if it requires a bit of reading and discussion in order to grasp it. And that it's every bit as interesting as selecting the right stones for your next fantasy 'scape.
In our world, there is a reason why we talk so much about ecology and arcane things, like the idea of allochthonous input into wild aquatic habitats. There is a reason why we devote hundreds of thousands of words to subjects like fungi, biofilms, and detritus. It's because an understanding of these topics is foundational to the work we do as botanical-style aquarium enthusiasts. When you understand these things, you're better equipped to understand what's happening in your aquairums.
It would have been much easier for me if I spent the last 6 years writing articles and doing podcasts on how to get the sexy look of a botanical-style aquarium. Yet, it would have left us simply another hollow, vapid purveyor of leaves and seed pods, passing the buck to someone else to cover these ideas, develop the operating fundamentals and philosophies which are applicable to the botanical-style aquarium methodology.
Not on my watch.
I'm going to continue discussing some of these seemingly arcane topics. Why? Well, for several reasons. First, because someone has to do it. Might as well be me; I play with this stuff every day of my life. Second, because it's so important to convey these fundamentals. It builds a movement and reinforces the methodology we all embrace. Third, because I feel that I have a responsibility to the hobby, and to the fishes we love. And finally, because it's hard. It's not easy to distill these complex ideas into digestible information. And that very fact makes it a worthwhile endeavour.
We all need to learn, understand, and share these types of topics.
Success in the aquarium hobby isn't that difficult- after you have a grasp of the fundamentals; an understanding of why we do what we do. However, the hobby isn't "easy" in the sense that you just toss your fishes into the water and call it a day. It takes some work. It should take some work. Because taking care of live animals, some of which are threatened in the wild, is a huge responsibility which should not be taken lightly.
So, maybe the tone of this piece is a little bit dark to some. It shouldn't be interpreted that way. Rather, it's a brutally honest call for us to make a better effort to understand and appreciate just how amazing what we as aquarists do every dingle day, and what responsibility goes along with these achievements. It's a call to wake up- look ourselves in the mirror as hobbyists, content creators, and industry types- and do better.
We can. There is enormous talent out there- and there has never been a time in history when its easier to disseminate useful information to a larger number of interested persons.
We just have to DO it. To not shirk this responsibility- and this gift.
It's not as hard as you think, and the benefits of the effort are remarkable.
Stay honest. Stay reflective. Stay creative. Stay observant. Stay inspired...
And Stay Wet.
They say that Nature abhors a vacuum...
Nature also seems to like to accumulate stuff, doesn't it?
Natural watercourses are really good at accumulating terrestrial materials, creating inviting habitats for fishes. They serve not only as physical locales for fishes to forage an hide amongst, they provide a huge habitat for a variety of other organisms which support the fishes.
And of course, these are compelling aquatic features for us fish geeks to replicate in our aquariums, aren't they? They are, and perhaps provide the basic "role model" for the botanical-style aquairum.
These aggregations of materials occur all the time in Nature, and they're caused by a variety of things; typically, weather events, which drive materials off of the trees overhead, or from the surrounding terrestrial habitats into the water. Currents caused by rising water levels move the materials along, until they might be caught up among various benthic features, like fallen trees, branches, rocks, etc.
Yeah, as you'd imagine, stream and river bottom composition is completely affected by things like weather, current, geology, the surrounding terrestrial habitat, and a host of other factors- all of which could make planning your next aquarium even more interesting if you take them into consideration!
According to one study I read, eventually, most of the organic debris is deposited on the stream bottom or drifts downstream until it becomes trapped by a variety of natural obstacles.
If we focus on streams, it's important to note that the volume of water entering the stream, and the depth of the channels it carves out, helps in part determine the amount and size of materials which accumulate, as well as the sediment particles that can be carried along, and thus comprise the substrate of this habitat. .
And of course, the composition of bottom materials and the depth of the channel are always changing in response to the flow in a given stream, affecting the composition and ecology in many ways.
Some leaf litter beds form in what stream ecologists call "meanders", which are stream structures that form when moving water in a stream erodes the outer banks and widens its "valley", and the inner part of the river has less energy and deposits silt- or in our instance, leaves.
There is a whole, fascinating science to river and stream structure, and with so many implications for understanding how these structures and mechanisms affect fish population, occurrence, behavior, and ecology, it's well worth studying for aquarium interpretation! Did you get that part where I mentioned that the lower-energy parts of the water courses tend to accumulate leaves and sediments and stuff?
Likely you did!
Permanent streams will often have different volume and material composition (usually finely-packed sands and gravels, with lots of smooth stones) than more intermittent streams, which are the result of inundation caused by rain, etc.
So-called "ephemeral" streams, typically occur only immediately after rain events (which means they usually don't have fish in them unless they are washed into them from more permanent watercourses). The latter two stream types are typically more affected by leaves, botanical debris, branches, and other materials.
In the Amazon region (you knew I was sort of headed back that way, right?), it sort of works both ways, with the rivers influencing the surrounding land...and then the land "giving" some of the materials back to the rivers...the extensive lowland areas bordering the river and its tributaries, known as varzeas (“floodplains”), are subject to annual flooding, which helps foster enrichment of the aquatic environment.
Land and water, working together, provide and amazing resource for the adventurous and interested hobbyist to explore in greater detail.
The important, and overriding Thieme of many aquatic habitats which we try to replicate in the hobby is that they accumulate quantities of terrestrial materials. These materials don't just impact the physical characteristics of these habitats, they influence the ecology as well. As we know by now, terrestrial materials, when submerged in water, leach soluble compounds into the water, impacting the chemistry.
They also tend to recruit fungal growths and biofilms, which in turn serve to not only decompose the terrestrial materials- they tend to attract fishes to graze upon them! Terrestrial materials form the basis of a rich, surprisingly complex aquatic ecology. A food web arises.
So, what exactly is a food web?
A food web is defined by aquatic ecologists as a series of "trophic connections" (ie; feeding and nutritional resources in a given habitat) among various species in an aquatic community.
All food chains and webs have at least two or three of these trophic levels. Generally, there are a maximum of four trophic levels. Many consumers feed at more than one trophic level.
So, a trophic level in our case would go something like this: Leaf litter, bacteria/fungal growth, crustaceans...
In the wild aquatic habitats we love so much, food webs are vital to the organisms which live in them. They are an absolute model for ecological interdependencies and processes which encompass the relationship between the terrestrial and aquatic environments.
Interestingly, in streams, the primary producers of the food webs that attract our fishes are...algae and diatoms, which are typically found on rocks and wood wherever light and nutrients create optimum conditions for their growth. Organic material that enters streams via leaf fall is acted upon by small organisms, which help break it down.
It is probably no surprise, then, that bacteria (especially in biofilms!) and fungi are the initial consumers of the organic materials that accumulate on the bottom. Like, the stuff many of us loathe. These, in turn, are extremely vital to fishes as a food source. Hence, one of the things I love so much about utilizing a leaf litter bed as a big part of your substrate composition in an aquarium!
We are able to establish rudimentary food webs in our aquariums. It's pretty easy, if we don't try to clean the crap out of our tanks and remove every bit of organic matter which we deem offensive to our aesthetic sensibilities! Remember, all of that material which we freak out about is someone's next meal, isn't it? It's consumed. The various organisms which arise when we allow leaves, branches, seed pods and other materials to accumulate and decompose in our tanks help see to that.
Yes, aquariums are different than wild aquatic habitats, but they have many characteristics which are analogous to them. And, sure, we typically don't maintain completely "open" systems, but I wonder just how much of the ecology of these fascinating habitats we can replicate in our tanks-and what potential benefits may be realized?
I'm willing to bet that it's a lot more than we think. However, we have to start somewhere, right?
It all starts with adding and accumulating terrestrial materials in our tanks, and allowing an ecology to grow up around them. It's that simple- and that complex, right? It falls on us- the hobbyists- NOT to go crazy and try to intervene too much. We need to exercise restraint- to let the natural processes which power our aquariums arise, assemble, and thrive.
That's my continuing challenge to our community..
Yeah, we have to let stuff go a bit. It's really hard for a lot of hobbyists to do this. We're essentially trained from the beginnings of our aquarium experience to scrub, polish, and siphon out everything which doesn't meet some definition of "acceptable."
We've been told that algae growth or fungal growths on our wood or substrate are bad, and must be removed. We've been encouraged to siphon out any decomposing materials, and that stuff like detritus is the source of untold disaster if we let it accumulate in our tanks.
It's hard to make this mental shift. I know. I've been trying to convince people to take this path for the better part of the past decade, and it's finally catching on. Skeptics and haters abound- more than ever, now, as these ideas have gained traction in the aquarium hobby.
It's 100% counterintuitive to everything we've been indoctrinated to believe. And worse, we're asking you to have faith that "stuff will work out" in your tank when you see all of this biofilm and fungal growth, turbid water, decomposition, and perhaps even algae. Stuff that the so-called "Nature Aquairum" crowd would absolutely shit their pants over.
Well, this IS Nature, boys and girls.
This is Planet Earth.
And yeah, you're actually not 100% in control. It's not the sanitized, organized, highly stylized "Nature" of your fantasies. It's the "Nature" that's perfectly imperfect, filled with non-ratioed, seemingly disorganized aggregations of materials, and life forms covering everything. You have to cede some of the work in your tank to Nature. You'll "go through some things." Some of the stuff you'll see will be "ugly" to you.
Or, will it be?
Will you perhaps study some of the wild aquatic habitats of the world where our fishes come from, see what makes them function the way that they do- and draw a parallel between what you're seeing in your tank, and what you're seeing in Nature?
Will you hang on?
Will you "wait out" what appears to be an endless explosion of gooey stringy stuff coming out of your leaves, wood, and and botanicals, and allow your tank to achieve it's own form of equilibrium? Or, will you reach for the siphon hose and pull it all out, disrupting some of Natures's most elegant, valuable, and efficient processes in order to "re-set" and achieve some sort of "instant gratification" that you were told that a spotless, sterile-looking tank will provide?
Yeah. Re-setting the whole thing.
Doing things the way we've done them in then hobby for decades because they give you the predictable results in a short amount of time...
Or, will you see the real beauty of unedited Nature in your very own tank? And the amazing way Nature works it out...If you let Her.
That's the adventure- the challenge of the botanical-style aquarium. A methodology filled with inexact, unconventional, yet well-known natural processes. A methodology which asks you to make some leaps of faith, some educated guesses, and to play some hunches. An evolving, not entirely predictable path to a dynamic, truly remarkable aquarium.
You can do this. You might fail, but you'll likely succeed, especially if you put your faith in Nature.
Be strong. Be patient. Be experimental.
Hang on through the weird, uncomfortable, uncertain, unknown stuff. It's worth it.
Stay bold. Stay open minded. Stay curious. Stay the course...
And Stay Wet.
I've always been fascinated by environments which transform from dry, terrestrial ones to lush aquatic ones during the course of the year. I remember as a kid visiting a little depression in a field near my home , which, every spring, with the rains would turn into a little pond, complete with frogs, Fairy Shrimp, and other life forms. I used to love exploring it, and was utterly transfixed by the unique and dynamic seasonal transition.
The thrill and fascination of seeing that little depression in the ground, which I later learned was called a "vernal" or "temporal" pool by ecologists, never quite left me. As a fish geek, I knew that one day I'd be able to incorporate what I had seen into my fish keeping hobby...somehow.
About 5 years ago, I got a real "bug up my ass", as they say, about the flooded forests of South America. There is something alluring to me about the way these habitats transition between terrestrial and aquatic at certain times of the year. The migration of fishes and the emergence of aquatic life forms in a formerly terrestrial environment fascinates me- as does the tenacity of the terrestrial organisms which hang on during these periods of inundation.
So, I began playing with aquariums configured to replicate the function and form of these unique habitats. I spent a lot of time studying the components of the Igapo and Varzea environments- the soils, plants, fauna, etc., and learning the influences which lead to their creation and function.
Once I had a grasp of the way these dynamic ecologies work, the task of attempting to recreate them in the aquarium became more realistic and achievable. I realized that, although hobbyists have created what they call "Igapo" simulations in biotope contests for years, for example, it was always a representation of the "wet" season. Essentially a living "diorama" of sorts. Not really a true simulation of the seasonal dynamics which create these habitats.
They were cool, but something was somehow missing to me. With those representations, you throw in some leaves, twigs, and seed pods, maybe a few plants, and call your tank a "flooded forest." I mean, essentially a botanical-style aquairum, although the emphasis was on appearance, not function. That wasn't really that difficult to do, nor much of a advancement in the current state of the art of aquarium keeping. I could do that already. Rather, I wanted to recreate the process- all of it- or as much as possible- in my aquariums.
Thus, the idea of the "Urban Igapo"- a functional representation of a transitional aquatic habitat was born.
The concept behind the "Urban Igapo" is pretty straightforward:
The idea is to replicate to a certain extent, the seasonal inundation of the forests and grasslands of of Amazonia by starting the tank in a 'terrestrial phase", then slowly inundating it with water over a period of weeks or more; then, running the system in an "aquatic phase" for the duration of the 'wet season", then repeating the process again and again.
Because you can do this in the comfort of your own home, we called the concept the "Urban Igapo." About 2 years ago, we went more in depth with some of the procedures and techniques that you'd want to incorporate into your own executions of the idea.
As with so many things in the modern aquarium hobby, there is occasionally some confusion and even misunderstandings about why the hell we do this in the first place!
Well, that's a good question! I mean, the whole idea of this particular approach is to replicate as faithfully as possible the seasonal wet/dry cycles which occur in these habitats. It starts with a dry or terrestrial environment, managed as such for an extended period of time, which is gradually flooded to simulate inundation which occurs when the rainy season commences and swollen rivers and streams overflow into the forest or grassland.
Sure, you can replicate the "wet season" only- absolutely. I've seen tons of tanks created by hobbyists to do this. However, if you want to replicate the seasonal cycle- the real magic of this approach- you'll find as I did that it's more fun to do the "dry season!"
Think of it in the context of what the aquatic environment is- a forest floor or grassland which has been flooded. If you develop the "hardscape" (gulp) for your tank with that it mind, it starts making more sense. What do you find on a forest floor or grassland habitat? Soil, leaf litter, twigs, seed pods, branches, grasses, and plants.
Just add water, right?
Well, sort of.
Now, recently, one of my friends who was presenting his experiences with this approach was just getting pounded on a forum by some, well- let's nicely call them "skeptics"- you know, the typical internet-brave "armchair expert" types- about why you'd do this and how it can't lead to a stable aquarium and how it's "not a blackwater aquarium" (okay, it wasn't presented as such, but it could be...) and that it's just a "dry start" (Well, sort of, but you have to understand the concept behind it, dude), and that you don't need to do it this way and...well- that kind of stuff.
I mean, the full compliment of negative, ignorant, questions by people clearly frightened about someone trying to do something a little differently. In a typical display of online-warrior hypocrisy, one particularly nasty hack did not even bother to research the idea or think about what it was really trying to do before laying into my friend.
Apparently, for these people, there was a lot to unpack.
I mean, first of all, the idea was not intended to be a "dry start" planted tank. It just wasn't. I mean, it starts out "dry", but that's where the similarity ends. This ignorant comment is a classic example of the way some hobbyists make assumptions based on a superficial understanding of something.
We aren't trying to grow aquatic plants here. It's about creating a habitat of terrestrial plants snd grasses, allowing them to establish, snd then inundating the display. Most of the terrestrial grasses will simply not survive extended periods of time submerged. Now, you COULD add adaptable aquatic plants- there are no "rules"- but the intention was to replicate a seasonal dynamic.
The other point, which is utterly lost on some people, is that establishing a "transitional" environment in an aquarium takes time and patience. One dummy literally called the process "complete nonsense" and a "waste of time." This is exactly the kind of self-righteous, ignorant hobbyist who will never get it. In fact, I'm surprised guys like that actually have any success at anything in the hobby.
Such a dismissive and judgmental attitude.
The wet season in The Amazon runs from November to June. And it rains almost every day. And what's really interesting is that the surrounding Amazon rain forest is estimated by some scientists to create as much as 50% of its own precipitation! Think about THAT for a minute. It does this via the humidity present in the forest itself, from the water vapor present on plant leaves- which contributes to the formation of rain clouds.
Yeah, trees in the Amazon release enough moisture through photosynthesis to create low-level clouds and literally generate rain, according to a recent study published in the Proceedings of the National Academy of Sciences (U.S.)!
But it makes a lot of sense, right?
Yet another reason why we need to protect these precious habitats. You cut down a tree in the Amazon- you're literally reducing the amount of rain that can be produced.
It's that simple.
That's really important. It's more than just a cool "cocktail party sound bite."
So what happens to the (aquatic) environment in which our fishes live in when it rains? What does the rain actually do?
Well, for one thing, rain performs the dual function of diluting organics, while transporting more nutrient and materials across the ecosystem. What happens in many of the regions of Amazonia, for example- is the evolution of our most compelling environmental niches. The water levels in the rivers rise significantly. often several meters, and the once dry forest floor fills with water from the torrential rain and overflowing rivers and streams.
The Igapos are formed.
Flooded forest floors.
The formerly terrestrial environment is now transformed into an earthy, twisted, incredibly rich aquatic habitat, which fishes have evolved over eons to live in and utilize for food, protection, and spawning areas.
All of the botanical material-shrubs, grasses, fallen leaves, branches, seed pods, and such, is suddenly submerged; often, currents re-distribute the leaves and seed pods and branches into little pockets and "stands", affecting the (now underwater) "topography" of the landscape.
Leaves begin to accumulate.
Soils dissolve their chemical constituents- tannins, and humic acids- into the water, enriching it. Fungi and micororganisms begin to feed on and break down the materials. Biofilms form, crustaceans multiply rapidly. Fishes are able to find new food sources; new hiding places..new areas to spawn.
So, yeah, the rains have a huge impact on tropical aquatic ecosystems. And it's important to think of the relationship between the terrestrial habitat and the aquatic one when visualizing the possibilities of replicating nature in your aquarium in this context.
It's an intimate, interrelated, "codependent" sort of arrangement!
To replicate this process is really not difficult. The challenging part is to separate what we are trying to do here from our preconceptions about how an aquarium should work. To understand that the resulting aquatic display won't initially look or function like anything that we're already familiar with.
While it superficially resembles the "dry start" method that many aquatic plant enthusiasts play with, it's important to remember that our goal isn't to start plants for a traditional aquarium. It's to establish terrestrial growth and to facilitate a microbiome of organisms which help create this habitat. It's to replicate, on some levels, the year-round dynamic of the Amazonian forests. We favor terrestrial plants- and grasses-grown from seed, to start the "cycle."
So, those of you who are ready to downplay the significance of experimenting with this stuff because "people have done 'dry start' planted tanks for years", take comfort in the fact that I recognize that, and acknowledge that we're taking a slightly different approach here, okay?
You'll need to create a technical means or set of procedures to gradually flood your "rainforest floor" in your tank, which could be accomplished manually, by simply pouring water into the vivarium over a series of days; or automatically, with solenoids controlling valves from a reservoir beneath the setup, or perhaps employing the "rain heads" that frog and herp people use in their systems. This is all very achievable, even for hobbyists like me with limited "DIY" skills.
You just have to innovate, and be willing to do a little busy work. You can keep it incredibly simple, and just utilize a small tank.
You must be patient.
And of course, there are questions. Here are some of the major/common ones we receive about this concept:
Does the grass and plants that you've grown in the "dry season" survive the inundation?
A great question. Some do, some don't. (How's that for concise info!). I've played with grasses which are immersion tolerant, such as Paspalum. This stuff will "hang around" for a while while submerged for about a month and a half to two months, in my experience, before ultimately succumbing. Sometimes it comes back when the "dry season" returns. However, when it doesn't survive, it decomposes in the now aquatic substrate, and adds to the biological diversity by cultivating fungi and bacteria.
You can use many plants which are riparian in nature or capable of growing emmersed, such as my fave, Acorus, as well as all sorts of plants, even aquatics, like Hydrocotyle, Cryptocoryne, and others. These can, of course, survive the transition between aquatic and "terrestrial" environments.
How long does the "dry season" have to last?
Well, if you want to mimic one of these habitats in the most realistic manner possible, follow the exact wet and dry seasons as you'd encounter in the locale you're inspired by. Alternatively, I'd at least go 2 months "dry" to encourage a nice growth of grasses and plants prior to inundation.
And of course, you cans do this over and over again! If you're trying to keep fishes like annual killifishes, the "dry season" could be used on the incubation period of their eggs.
When you flood the tank, doesn't it make a cloudy mess? Does the water quality decline rapidly?
Sure, when you add water to what is essentially a terrestrial "planter box", you're going to get cloudiness, from the sediments and other materials present in the substrate. You will have clumps of grasses or other botanical materials likely floating around for a while.
Surprisingly, in my experience, the water quality stays remarkably good for aquatic life. Now, I'm not saying that it's all pristine and crystal clear; however, if you let things settle out a bit before adding fishes, the water clears up and a surprising amount of life (various microorganisms like Paramecium, bacteria, etc.) emerges.
Curiously, I personally have NOT recorded ammonia or nitrite spikes following the inundation. That being said, you can and should test your water before adding fishes. You can also dose bacterial inoculants, like our own "Culture" or others, into the water to help. The Purple Non-Sulphur bacteria in "Culture" are extremophiles, particularly well adapted to the dynamics of the wet/dry environment.
Should I use a filter in the "wet season?"
You certainly can. I've gone both ways, using a small internal filter or sponge filter in some instances. I've also played with simply using an air stone. Most of the time, I don't use any filtration. I just conduct partial water exchanges like I would with any other tank- although I take care not to disturb the substrate too much if I can. When I scaled up my "Urban Igapo" experiments to larger tanks (greater than 10 gallons), Il incorporated a filters with no issues.
A lot of what we do is simply letting Nature "take Her course."
Ceding a lot of the control to Nature is hard for some to quantify as a "technique" or "method", so I get it. At various phases in the process, our "best practice" might be to simply observe...
And with plant growth slowing down, or even going completely dormant while submerged, the utilization of nutrients via their growth diminishes, and aquatic life forms (biofilms, algae, aquatic plants, and various bacteria, microorganisms, and microcrustaceans) take over. There is obviously an initial "lag time" when this transitional phase occurs- a time when there is the greatest opportunity for one life form or another (algae, bacterial biofilms, etc.) to become the dominant "player" in the microcosm.
It's exactly what happens in Nature during this period, right?
And there are parallels in the management of aquariums.
In our aquarium practice, it's the time when you think about the impact of technique-such as water exchanges, addition of aquatic plants, adding fishes, reducing light intensity and photoperiod, etc. and (again) observation to keep things in balance- at least as much as possible. You'll question yourself...and wonder if you should intervene- and how..
It's about a number of measured moves, any of which could have significant impact- even "take over" the system- if allowed to do so. This is part of the reason why we don't currently recommend playing with the Urban Igapo idea on a large-tank scale just yet. (that, and the fact that we're not going to be geared up to produce thousands of pounds of the various substrates just yet! 😆)
Until you make those mental shifts to accept all of this stuff in one of these small tanks, the idea of replicating this in 40-50, or 100 gallons is something that you may want to hold off on for just a bit.
I mean, if you understand and accept the processes, functions, and aesthetics of this stuff, maybe you wouldwant to "go big" on your first attempt. However, I think you need to try it on a "nano scale" first, to really "acclimate" to the idea.
The idea of accepting Nature as it is makes you extremely humble, because there is a realization at some point that you're more of an "interested observer" than an "active participant." It's a dance. One which we may only have so much control- or even understanding of! That's part of the charm, IMHO.
These habitats are a remarkable "mix" of terrestrial and aquatic elements, processes, and cycles. There is a lot going on. It's not just, "Okay, the water is here- now it's a stream!"
Nope. There is a lot of stuff to consider.
In fact, one of the arguments one could make about these "Urban Igapo" systems is that you may not want to aggressively intervene during the transition, because there is so much going on! Rather, you may simply want toobserve and study the processes and results which occur during this phase. Personally, I've noticed that the "wet season" changes in my UI tanks generally happen slowly, but you will definitely notice them as they occur.
After you've run through two or three complete "seasonal transition cycles" in your "Urban Igapo", you'll either hate the shit out of the idea- or you'll fall completely in love with it, and want to do more and more work in this alluring little sub-sector of the botanical-style aquarium world.
The opportunity to learn more about the unique nuances which occur during the transition from a terrestrial to an aquatic habitat is irresistible to me. Of course, I'm willing to accept all of the stuff with a very open mind. Typically, it results in a fascinating, utterly beautiful, and surprisingly realistic representation of what happens in Nature.
It's also entirely possible to have your "Urban Igapo" turn into an "Urban Algae Farm" if things get out of balance. Yet, it can "recover" from this. Again, even the fact that a system is "out of balance" doesn't mean that it's a failure. After all, the algae is thriving, right? That's a success. Life forms have adapted. A cause to celebrate.
It happens in Nature, too!
So, that's a brief rundown on the dynamics and challenges of the "Urban Igapo" concept. It will be exciting to see how each of us evolves the idea further!
Stay creative. Stay thoughtful. Stay bold. Stay curious...
And Stay Wet.
One of the things that drives most hobbyists crazy is when "stuff" gets blown around, covered or moved about in the aquarium. It can be because of strong current, the activity of fishes, or simply overgrown by plants. I understand the annoyance that many hobbyists feel; I recall this same aggravating feeling in many reef tanks where I had high flow and sand on the bottom- almost always a combination for annoyance!
I mean, I get it. We have what feel is a carefully thought-out aquascape, looking exactly how we expected it would after setup. Yet, despite our ideas and thoughts, stuff moves around in the aquarium. It's something we can either accept, or modify in our aquariums, depending upon our preferences.
Yet, movement and "covering" of various materials by sediments, biofilms, etc., which accumulate on the substrate in natural habitats are everyday occurrences, and they help forge a very dynamic ecosystem. And they are constantly creating new opportunities for the fishes which reside in them to exploit.
When you think about how materials "get around" in the wild aquatic habitats, there are a few factors which influence both the accumulation and distribution of them. In many topical streams, the water depth and intensity of the flow changes during periods of rain and runoff, creating significant re-distribution of the materials which accumulate on the bottom, such as leaves, branches, seed pods, and the like.
Larger, more "hefty" materials, such as branches, submerged logs, etc., will tend to move less frequently, and in many instances, they'll remain stationary, providing a physical diversion for water as substrate materials accumulate around them.
A "dam", of sorts, if you will.
And this creates known structures within streams in areas like Amazonia, which are known to have existed for many years. Semi-permanent aquatic features within the streams, which influence not only the physical and chemical environment, but the very habits and abundance of the fishes which reside there.
Most of the small stuff, like leaves, tend to move around quite a bit... One might say that the "material changes" created by this movement of materials can have significant implications for fishes. As we've talked about before, they follow the food, often existing in, and subsisting off of what they can find in these areas.
New accumulations of leaves, detritus, and other materials benefit the entire ecosystem.
In the case of our aquariums, this "redistribution" of material can create interesting opportunities to not only switch up the aesthetics of our tanks, but to provide new and unique little physical areas for many of the fishes we keep.
And yeah, the creation of new feeding opportunities for life forms at all levels is a positive which simply cannot be overstated! As hobbyists, we tend to lament changes to the aquascape of our tanks caused by things outside of our control, and consider them to be a huge inconvenience, when in reality, they're not only facsimile of very natural dynamic processes-they are fundamental to their evolution.
The benthic microfauna which our fishes tend to feed on also are affected by this phenomenon, and as mentioned above, the fishes tend to "follow the food", making this a case of the fishes adapting to a changing environment. And perhaps...maybe...the idea of fishes sort of having to constantly adjust to a changing physical environment could be some sort of "trigger", hidden deep in their genetic code, that perhaps stimulates overall health, immunity or spawning?
Something in their "programing" that says, "You're at home..." Perhaps something which triggers specific adaptive behaviors?
I find this possibility fascinating, because we can learn more about our fishes' behaviors, and create really interesting habitats for them simply by adding botanicals to our aquariums and allowing them to "do their own thing"- to break apart as they decompose, move about as we change water or conduct maintenance activities, or add new pieces from time to time.
Again, just like Nature.
We just need to "get over ourselves" on this aesthetic thing!
Another mental shift? Yeah, it is. An easy one, but one that we need make, really.
Like any environment, botanical/ leaf litter beds have their own "rhythm", fostering substantial communities of fishes. The dynamic behind this biotope can best be summarized in this interesting excerpt from an academic paper on blackwater leaf-litter communities by biologist Peter Alan Henderson, that is useful for those of us attempting to replicate these communities in our aquaria:
"..life within the litter is not a crowded, chaotic scramble for space and food. Each species occupies a sub-region defined by physical variables such as flow and oxygen content, water depth, litter depth and particle size…
...this subtle subdivision of space is the key to understanding the maintenance of diversity. While subdivision of time is also evident with, for example, gymnotids hunting by night and cichlids hunting by day, this is only possible when each species has its space within which to hide.”
In other words, different species inhabit different sections of the leaf litter beds. As aquarists, we should consider this when creating and stocking our botanical-style aquariums.
It just makes sense, right?
So, when you're attempting to replicate such an environment, consider how the fishes would utilize each of the materials you're working with. For example, leaf litter areas would be an idea shelter for many juvenile fishes, catfishes, and even young cichlids to shelter among.
Submerged branches, larger seed pods and other botanicals provide territory and areas where fishes can forage for macrophytes (algal growths which occur on the surfaces of these materials). Fish selection can be influenced as much by the materials you're using to 'scape the tank as anything else, when you think about it!
And it's not just fishes, of course. It's a multitude of life forms.
There are numerous life forms which are found on ad among these materials as well, such as fungal growths, bacterial biofilms, etc. which we likely never really consider, yet are found in abundance in nature and in the aquarium, and perform vital roles in the function of the aquatic habitat.
Perhaps most fascinating and rarely discussed in the hobby, are the unique freshwater sponges, from the genus Spongilla. Yes, you heard. Freshwater sponges! These interesting life forms attach themselves to rocks and logs and filter the water for various small aquatic organisms, like bacteria, protozoa, and other minute aquatic life forms. Some are truly incredible looking organisms!
(Spongilla lacustris Image by Kirt Onthank. Used under CC-BY SA 3.0)
Unlike the better-known marine sponges, freshwater sponges are subjected to the more variable environment of rivers and streams, and have adapted a strategy of survival. When conditions deteriorate, the organisms create "buds", known as "gemmules", which are an asexually reproduced mass of cells capable of developing into a new sponge! The Gemmules remain dormant until environmental conditions permit them to develop once again!
To my knowledge, these organisms have never been intentionally collected for aquariums, and I suspect they are a little tricky to transport (despite their adaptability), just ike their marine cousins are. One species, Metania reticulata, is extremely common in the Brazilian Amazon. They are found on rocks, submerged branches, and even tree trunks when these areas are submerged, and remain in a dormant phase in the aforementioned gemmules during periods of desiccation!
Now, I'm not suggesting that we go and collect freshwater sponges for aquarium use, but I am curious if they occur as "hitchhikers" on driftwood, rocks or other materials which end up in our aquariums. When you think about how important sponges are as natural "filters", one can only wonder how they might perform this beneficial role in the aquarium as well!
We've encountered them in reef tanks for many years...I wonder if they could ultimately find their way into our botanical-style aquariums as well? Perhaps they already have. Have any of you encountered one before in your tanks?
The big takeaway from all of this: A botanical bed in our aquariums and in Nature is a physical structure, ephemeral though it may be- which functions just like an aggregation of branches, or a reef, rock piles, or other features would in the wild benthic environment, although perhaps even "looser" and more dynamic.
Stuff gets redistributed, covered, and often breaks down over time. Exactly like what happens in Nature.
Think about the possibilities which are out there, under every leaf. Every sunken branch. Every root. Every rock.
It's all brought about by the dynamic process of movement.
Perhaps instead of looking at the movement of stuff in our tanks as an annoyance, we might enjoy it a lot more if we look at it as an opportunity! An opportunity to learn more about the behaviors and life styles of our fishes and their ever-changing environment.
Stay observant. Stay creative. Stay excited. Stay open-minded...
And Stay Wet.
One of the questions which we are asked less and less these days is, 'What kinds of fishes are suitable for a botanical-style aquarium?" I think that after 6 years of pounding all of these ideas into your heads about all of the strange nuances of botanical-style aquariums, it's almost universally understood that pretty much any fishes can live in them.
On the other hand, when it comes to how we stock our tanks, nothing has really changed...however, it could. And it should, IMHO.
We spend a pretty good amount of time studying, scheming, and pondering how to create a compatible, interesting, and attractive community of fishes within our aquariums.
It's probably among the most enjoyable things that we do in the hobby, right?
As a somewhat eccentric philosopher of all things fish, one of my favorite things to ponder is stuff that we do while creating our aquariums which is- intentionally or otherwise- analogous to the factors in Nature that result in the environments and fish populations that we find so compelling.
If you're like me, you likely spend a little too much time pondering all sorts of arcane aspects of the hobby...Okay, so maybe you're NOT like me, but you probably have a rather keen interest in the way Nature operates in the wild aquatic systems of the world, and stock your aquariums accordingly.
As one who studies a lot of details about some of the habitats from which our fishes come, I can't help but occasionally wonder exactly what it is that brings fishes to a given location or niche within a environment?
Now, the first answer we're likely to proffer is the most apparent...right? I mean, they follow the food!
Fishes tend to move into new areas in search suitable food sources as part of their life cycle. And food sources often become available in habitats such as flooded forest areas after the rains come, when decomposing leaves and botanical materials begin to create (or re-activate, as the case may be) "food webs", attracting ever more complex life forms into the area.
When we create our aquariums, we take into consideration a lot of factors, ranging from the temperament and size of our fish selections, to their appearance, right? These are all important factors. However, have you ever considered what the factors are in nature which affect the composition of a fish community in a given habitat?
Like, why "x" fish is living in a particular habitat?
What adaptations has the fish made that make it uniquely suitable for this environmental niche? Further, have you thought about how we as hobbyists replicate, to some extent, the actual selection processes which occur in Nature in our quest to create the perfect community aquarium?
Now, if you're an African Cichlid lover or reef hobbyist, I'm sure you have!
Social hierarchies, spatial orientations, and allopathic processes are vital to success in those types of aquariums; you typically can't get away with just throwing in a random fish or coral and hoping it will just mix perfectly.
However, for many hobbyists who aim to construct simple "community tanks", it isn't that vital to fill specific niches and such...we probably move other factors to the forefront when thinking about possible additions to our community of fishes: Like, how cool the fish looks, how large it grows, if it has a peaceful temperament, etc. More basic stuff.
However, in the end, we almost always make selections based upon factors which we deem important...again, a sort of near-mimicry of natural processes- and how the fishes work in the habitat we've created for them.
"Unnatural selection?" Or...Is it essentially what nature's does for eons?
Oh, and what exactly is an "aquatic habitat", by the way? In short, you could say that an aquatic habitat is the physical, chemical, and biological characteristics which determine the suitability for habitation and reproduction of fishes.
Of course, these characteristics can determine which fishes are found in a given area in the wild- pretty much without exception. It's been happening for eons.
Approaching the stocking of an aquarium by determining which fishes would be appropriate for the physical characteristics of the tank is not exactly groundbreaking stuff.
However, when we evaluate this in the context of "theme", and what fish would be found within, say, an Amazonian Igarape stream or a Southeast Asian peat swamp, the idea of adding fishes to "exploit" the features of the habitat we've created is remarkably similar to the processes which occur in Nature that determine what fish are found there, and it's the ultimate expression of good tank planning, IMHO.
It's just kind of interesting to think about in that context, right?
Competition is another one of the important factors in determining how fish populations in the wild. Specifically, competition for space, resources (e.g.; food) and mates are prevalent. In our aquariums, we do see this to some extent, right? The "alpha male" cichlid, the Pleco that gets the best cave, and the Tetra which dominates his shoal.
How we create the physical space for our fishes can have significant impact on this behavior. When good hiding spaces are at a premium, as are available spawning partners, their will be some form of social hierarchy, right?
Other environmental factors, such as water movement, dissolved oxygen, etc. are perhaps less impactful on our community once the tank is established. However, these factors figure prominently in our decisions about the composition of, or numbers or fishes in the community, don't they?
For example, you're unlikely to keep Hillstream loaches in a near stagnant, blackwater swamp biotope aquarium, just like you'd be unlikely to keep Altum Angelfish in a fast-moving stream biotope representation. And fishes which shoal or school will, obviously, best be kept in numbers.
"Aquarium Keeping 101", again.
One factor that we typically don't have in our aquaria is predation. I know very few aquarists who would be sadistic enough to even contemplate trying to keep predators and prey in the same tank, to let them "have at it" and see what happens, and who comes out on top!
I mean, there is a lot to this stuff, isn't there?
Again, the idea of creating a tank to serve the needs of certain fishes isn't earth-shattering. Yet, the idea of stocking the tank based on the available niches and physical characteristics is kind of a cool, educational, and ultimately very gratifying process. I just think it's truly amazing that we're able to actually do this these days.
And the sequence that you stock your tank in is extremely pertinent.
I think that you could literally create a sort of "sequence" to stocking various types of fishes based on the stage of "evolution" that your aquarium is in, although the sequence might be a bit different than Nature in some cases. For example, in a more-or-less brand new aquarium, analogous in this case to a newly-inundated forest floor, their might be a lot less in the way of lower life forms, such as fungi and bacteria, until the materials begin breaking down. You'd simply have an aggregation of fresh leaves, twigs, seed pods, soils, etc. in the habitat.
So, if anything, you're likely to see fishes which are much more dependent upon allochthonous input...food from the terrestrial environment. This is a compelling way to stock an aquarium, I think. Especially aquarium systems like ours which make use of these materials en masse.
Right from the start (after cycling, of course!), it would not be unrealistic to add fishes which feed on terrestrial fruits and botanical materials, such as Colossoma, Arowanna, Metynis, etc. Fishes which, for most aquarists of course, are utterly impractical to keep because of their large adult size and/or need for physical space!
(Pacu! Image by Rufus46, used under CC BY-SA 3.0)
Now, a lot of smaller, more "aquarium suited" fishes will also pick at these fruits and seeds, so you're not totally stuck with the big brutes if you want to go this route! Interestingly, the consumption and elimination of fruits by fishes is thought to be a major factor in the distribution of many plants in the region.
Do a little research here and you might be quite surprised about who consumes what in these habitats!
More realistically for most aquarists, I'd think that you could easily stock first with fishes like surface-dwelling (or near surface-dwelling) species, like hatchetfishes and some Pencilfishes, which are largely dependent upon terrestrial insects such as flies and ants, in Nature. In other words, they tend to "forage" or "graze" little, and are more opportunistic, taking advantage of careless insects which end up in the water of these newly-inundated environs.
I've read studies where almost 100 species were documented which feed near-exclusively on insects and arthropods from terrestrial sources in these habitats! As I mention often, if you dive a bit deeper than the typical hobbyist writings, and venture into scholarly materials and species descriptions, you'll be fascinated to read about the gut-content analysis of fishes, because they give you a tremendous insight about what to feed in the aquarium!
Continuing on, it's easy to see that, as the environments evolve, so does the fish population. And the possibilities for simulating this in the aquarium are many and are quite interesting!
Later, as materials start to decompose and are acted on by fungi and bacteria, you could conceivably add more of the "grazing" type fishes, such as Plecos, small Corydoras, Headstanders, etc.
As the tank ages and breaks in more, this would be analogous to the period of time when micro-crustaceans and aquatic insects are present in greater numbers, and you'd be inclined to see more of the "micropredators" like characins, and ultimately, small cichlids.
Interestingly, scientists have postulated that evolution favored small fishes like characins in these environments, because they are more efficient at capturing small terrestrial insects and spiders in these flooded forests than the larger fishes are!
And it makes a lot of sense, if you look at it strictly from a "density/variety" standpoint- lots of characins call these habitats home!
Then there are detritivores.
The detrivorus fishes remove large quantities of this material from submerged trees, branches, etc. Now, you might be surprised to learn that, in the wild, the gut-content analysis of almost every fish indicates that they consume organic detritus to some extent! And it makes sense...They work with the food sources that are available to them!
At different times of the year, different food sources are easier to obtain.
And, of course, all of the fishes which live in these habitats contribute to the surrounding forests by "recycling" nutrients locked up in the detritus. This is thought by ecologists to be especially important in blackwater inundated forests and meadows in areas like The Pantanal, because of the long periods of inundation and the nutrient-poor soils as a result of the slow decomposition rates.
All of this is actually very easy to replicate, to a certain extent, when stocking our aquaria. Why would you stock in this sort of sequence, when you're likely not relying on decomposing botanicals and leaves and the fungal and microbial life associated with them as your primary food source?
Well, you likely wouldn't be...However, what about the way that the fishes, when introduced at the appropriate "phase" in the tank's life cycle- adapt to the tank? Wouldn't the fishes take advantage of these materials as a supplement to the prepared foods that you're feeding them? Doesn't this impact the fishes' genetic "programming" in some fashion? Can it activate some health benefits, behaviors, etc?
I believe that it can. And I believe that this type of more natural feeding ca profoundly and positively impact our fishes' health.
I’m no genius, trust me. I don’t have half the skills many of you do but I have succeeded with many delicate “hard-to-feed” fishes over my hobby “career.”
Because I'm really patient.
Success with this approach is simply a result of deploying "radical patience." The practice of just moving really slowly and carefully when adding fishes to new tanks.
It's a really simple concept.
The hard part is waiting longer to add fishes.
Wait a minimum of three weeks—and even up to a month or two if you can stand it, and you will have a surprisingly large population of micro and macro fauna upon which your fishes can forage between feedings.
Having a “pre-stocked” system helps reduce a considerable amount of stress for new inhabitants, particularly for wild fishes, or fishes that have reputations as “delicate” feeders.
And think about it. This is really a natural analog of sorts. Fishes that live in inundated forest floors (yeah, the igapo again!) return to these areas to "follow the food" once they flood.
It just takes a few weeks, really. You’ll see fungal growth. You'll see some breakdown of the botanicals brought on by bacterial action or the feeding habits of small crustaceans and fungi. If you "pre-stock", you might even see the emergence of a significant population of copepods, amphipods, and other creatures crawling about, free from fishy predators, foraging on algae and detritus, and happily reproducing in your tank.
We kind of know this already, though- right?
This is really analogous to the tried-and-true practice of cultivating some turf algae on rocks either in or from outside your tank before adding herbivorous, grazing fishes, to give them some "grazing material."
Radical patience yields impressive results.
It’s not always easy to try something a little out of the ordinary, or a bit against the grain of popular practice, but I commend you for even thinking about the idea. At the very least, it may give you pause to how you stock your tank in the future, like "Herbivores first, micro predators last", or whatever thought you subscribe to.
Allow your system to mature and develop at least some populations of fauna for these fishes to supplement their diets with. You’ll develop a whole new appreciation for how an aquarium evolves when you take this long, but very cool road.
Stay patient. Stay observant. Stay creative. Stay studious. Stay resourceful...
And Stay Wet.
As you know, we've spent the better part of the past 6 years talking about every aspect of the botanical-style aquarium that we can think of. We've talked about techniques, approaches, ideas, etc. And we've spent a lot of time sharing information about wild aquatic habitats that we might be interested in replicating in both form and function.
However, I think we haven't spent as much time as we should talking about how botanicals "behave" in wild aquatic habitats. Much of this stuff has implications for those of us who are interested in replicating these habitats in our aquariums. So, let's dive in a bit more on this topic today!
Among the trees of the flooded forests, after the fruits mature (which occurs at high water levels), seeds will fall into the water and may float on the surface or be submerged for a number of weeks. Ecologists believe that the seed production of the trees coincides with the flood pulses, which facilitates their dispersal by water movement, and by the actions of fish.
Interestingly, scientists postulate that these floating or sinking seeds, which germinate and establish seedlings after the flood waters recede, do very well, sprouting and establishing themselves quickly, and are not severely affected by waterlogging in most species.
So, within their cycle of life, the trees take advantage of the water as part of their ecological adaptation. Trees in these areas have developed specialized morphologies, such as advantageous roots, butress systems and stilt roots.
In a lot of wild aquatic habitats where leaf litter and other allochthonous materials accumulate, there are a number of factors which control the density, size, and type of materials which are deposited in streams and such. The flow rate of the water within these habitats determines a lot of things, such as the size of the leaves and other botanical materials and where in the stream they are deposited.
I often wonder how much the fallen leaves and seed pods impact the water chemistry in a given stream, pond, or section of an Amazonian flooded forest. I know that studies have been done in which ecologists have measured dissolved oxygen and conductivity, as well as pH. However, those readings only give us so much information.
We hear a lot of discussion about blackwater habitats among hobbyists, and the implications for our aquariums. And part of the game here is understanding what it is that makes this a blackwater river system to begin with. We often hear that blackwater is "low in nutrients."
What exactly does this mean?
One study concluded that the Rio Negro is a blackwater river in large part because the very low nutrient concentrations of the soils that drain into it have arisen as a result of "several cycles of weathering, erosion, and sedimentation." In other words, there's not a whole lot of minerals and nutrients left in the soils to dissolve into the water to any meaningful extent!
Black-waters, drain from older rocks in areas like the Negro river, result from dissolved fulvic and humic substances, present small amounts of suspended sediment, lower pH (4.0 to 6.0) and dissolved elements. Yes, highly leached tropical environments where most of the soluble elements are quickly removed by heavy rainfall.
Perhaps...another reason (besides the previously cited limitation of light penetration) why aquatic plants are rather scare in these waters? It would appear that the bulk of the nutrients found in these blackwaters are likely dissolved into the aquatic environment by decomposing botanical materials, such as leaves, branches, etc.
Why does that sound familiar?
Besides the color, of course, the defining characteristics of blackwater rivers are pH values in the range of 4-5, low electrical conductivity, and minimal mineral content. Dissolved minerals, such as Ca, Mg, K, and Na are negligible. And with these low amounts of dissolved minerals come unique challenges for the animals who reside in these systems.
How do fishes survive and thrive in these rather extreme habitats?
It's long been known that fishes are well adapted to their natural habitats, particularly the more extreme ones. And this was borne out in a recent study of the Cardinal Tetra. Lab results suggest that humic substances protect cardinal tetras in the soft, acidic water in which they resides by preventing excessive sodium loss and stimulating calcium uptake to ensure proper homeostasis.
This is pretty extraordinary, as the humic substances found in the water actually enable the fishes to survive in this highly acidic water which is devoid of much mineral content typically needed for fishes to survive!
And of course, botanicals, leaves, and wood typically have an abundance of these humic substances, right? They are useful for more than just an interesting and unique aesthetic effect! There is a lot of room for research about influencing the overall environment in our aquariums here! I think we've barely scratched the surface of the potential for utilizing botanicals in our aquariums.
This is another one of those foundational aspects of the natural style of aquarium that we espouse. The understanding that processes like decomposition and physical transformation of the materials that we utilize our tanks are normal, expected, and beautiful things requires us to make mental shifts.
Botanical materials don't have nearly as much impact on the water parameters (other than say, conductivity and dissolved oxygen) as the soils do. These waters have high concentrations of humic and fulvic acids derived from sandy "hydromorphic podsols" prevalent in the region. However, these allochthonous materials have huge impact on the ecology of these systems!
Leaf litter, as one might suspect, is of huge importance in these ecosystems. Especially in smaller tributaries. In one study which I came across, it was concluded that, "The smaller the stream, the more dependent the biota is on leaf litter habitats and allocthonous energy derived directly or indirectly from the forest." (Kemenes and Forsberg)
From the same study, it was concluded that the substrate of the aquatic habitat had significant influence on the feeding habits of the fishes which resided in them:
"The biomass of allocthonous insectivore increased in channels with a higher percentage of sandy bottom substrate. Detritivorous insectivore biomass, in contrast, increased significantly in channels with a higher percentage of leaf substrate. General insectivores tended to increase in streams with higher proportions of leafy substrate, too.
Whats the implication for us as hobbyists? Well, for one thing, we can set up the benthic environment in our tanks to represent the appropriate environment for the fishes which we want to keep in them. Simple as that!
t's as much about function as anything else. And, about pushing into some new directions. The unorthodox aesthetics of these unusual aquariums we play with just happen to be an interesting "by-product" of theirfunction.
I personally think that almost every botanical-style aquarium can benefit from the presence of leaves. As we've discussed numerous times, leaves are the "operating system" of many natural habitats (ecology-wise), and perform a similar role in the aquarium.
The presence of botanical materials such as leaves in these aquatic habitats is fundamental. Leaves and other botanicals are extremely pervasive in almost every type of aquatic habitat.
In the tropical species of trees, the leaf drop is important to the surrounding environment. The nutrients are typically bound up in the leaves, so a regular release of leaves by the trees helps replenish the minerals and nutrients which are typically depleted from eons of leaching into the surrounding forests.
Now, interestingly enough, most tropical forest trees are classified as "evergreens", and don't have a specific seasonal leaf drop like the "deciduous" trees than many of us are more familiar with do...Rather, they replace their leaves gradually throughout the year as the leaves age and subsequently fall off the trees.
The implication here?
There is a more-or-less continuous "supply" of leaves falling off into the jungles and waterways in these habitats, which is why you'll see leaves at varying stages of decomposition in tropical streams. It's also why leaf litter banks may be almost "permanent" structures within some of these bodies of water!
Our botanical-style aquariums are not "set-and-forget" systems, and require basic maintenance (water exchanges, regular water testing, filter media replacement/cleaning), like any other aquarium. They do have one unique "requirement" as part of their ongoing maintenance which other types of aquariums seem to nothave: The "topping off" of botanicals as they break down.
The "topping off" of botanicals in your tank accomplishes a number of things: first, it creates a certain degree of environmental continuity- keeping things consistent from a "botanical capacity" standpoint. Over time, you have the opportunity to establish a "baseline" of water parameters, knowing how many of what to add to keep things more-or-less consistent, which could make the regular "topping off" of botanicals a bit more of a "science" in addition to an "art."
In addition, it keeps a consistent aesthetic "vibe" in your aquarium. Consistent, in that you can keep the sort of "look" you have, while making subtle- or even less-than-subtle "enhancements" as desired.
And, of course, "topping off" botanicals helps keeps you more intimately "in touch" with your aquarium, much in the same way a planted tank enthusiast would by trimming plants, or a reefer while making frags. When you're actively involved in the "operation" of your aquarium, you simply notice more. You can also learn more; appreciate the subtle, yet obvious changes which arise on an almost daily basis in our botanical-style aquariums.
I dare say that one of the things I enjoy doing most with my blackwater, botanical-style aquariums (besides just observing them, of course) is to "top off" the botanical supply from time to time. I feel that it not only gives me a sense of "actively participating" in the aquarium- it provides a sense that you're doing something nature has done for eons; something very "primal" and essential. Even the prep process is engaging.
Think about the materials which accumulate in natural aquatic habitats, and how they actually end up in them, and it makes you think about this in a very different context. A more "holistic" context that can make your experience that much more rewarding. Botanicals should be viewed as "consumables" in our hobby- much like activated carbon, filter pads, etc.- they simply don't last indefinitely.
Many seed pods and similar botanicals contain a substance known as lignin. Lignin is defined as a group of organic polymers which are essentially the structural materials which support the tissues of vascular plants. They are common in bark, wood, and yeah- seed pods, providing protection from rotting and structural rigidity.
In other words, they make seed pods kinda tough.
Yet, not permanent.
That being said, they are typically broken down by fungi and bacteria in aquatic environments. Inputs of terrestrial materials like leaf litter and seed pods into aquatic habitats can leach dissolved organic carbon (DOC), rich in lignin and cellulose. Factors like light intensity, mineral hardness, and the composition of the aforementioned bacterial /fungal community all affect the degree to which this material is broken down into its constituent parts in this environment.
Hmm...something we've kind of known for a while, right?
So, lignin is a major component of the "stuff" that's leached into our aquatic environments, along with that other big "player"- tannin.
Tannins, according to chemists, are a group of "astringent biomolecules" that bind to and precipitate proteins and other organic compounds. They're in almost every plant around, and are thought to play a role in protecting the plants from predation and potentially aid in their growth. As you might imagine, they are super-abundant in...leaves. In fact, it's thought that tannins comprise as much as 50% of the dry weight of leaves!
And of course, tannins in leaves, wood, soils, and plant materials tend to be highly water soluble, creating our beloved blackwater as they decompose. As the tannins leach into the water, they create that transparent, yet darkly-stained water we love so much!
In simplified terms, blackwater tends to occur when the rate of "carbon fixation" (photosynthesis) and its partial decay to soluble organic acids exceeds its rate of complete decay to carbon dioxide (oxidation).
Chew on that for a bit...Try to really wrap your head around it...
And sometimes, the research you do on these topics can unlock some interesting tangential information which can be applied to our work in aquairums...
Interesting tidbit of information from science: For those of you weirdos who like using wood, leaves and such in your aquariums, but hate the brown water (yeah, there are a few of you)- you can add baking soda to the water that you soak your wood and such in to accelerate the leaching process, as more alkaline solutions tend to draw out tannic acid from wood than pH neutral or acidic water does. Or you can simply keep using your 8.4 pH tap water!
"ARMCHAIR SPECULATION": This might be a good answer to why some people can't get the super dark tint they want for the long term...If you have more alkaline water, those tannins are more quickly pulled out. So you might get an initial burst, but the color won't last all that long...
I think just having a bit more than a superficial understanding of the way botanicals and other materials interact with the aquatic environment, and how we can embrace and replicate these systems in our own aquariums is really important to the hobby. The real message here is to not be afraid of learning about seemingly complex chemical and biological nuances of blackwater systems, and to apply some of this knowledge to our aquatic practice.
It can seem a bit intimidating at first, perhaps even a bit contrarian to "conventional aquarium practice", but if you force yourself beyond just the basic hobby-oriented material out there on these topics (hint once again: There aren't many!), there is literally a whole world of stuff you can learn about!
It starts by simply looking at Nature as an overall inspiration...
Wondering why the aquatic habitats we're looking at appear the way they do, and what processes create them. And rather than editing out the "undesirable" (by mainstream aquarium hobby standards) elements, we embrace as many of the elements as possible, try to figure out what benefits they bring, and how we can recreate them functionally in our closed aquarium systems.
There are no "flaws" in Nature's work, because Nature doesn't seek to satisfy observers. It seeks to evolve and change and grow. It looks the way it does because it's the sum total of the processes which occur to foster life and evolution.
We as hobbyists need to evolve and change and grow, ourselves.
We need to let go of our long-held beliefs about what truly is considered "beautiful." We need to study and understand the elegant way Nature does things- and just why natural aquatic habitats look the way they do. To look at things in context. To understand what kinds of outside influences, pressures, and threats these habitats face.
And, when we attempt replicate these functions in our aquariums, we're helping to grow this unique segment of the aquarium hobby.
Please make that effort to continue to educate yourself and get really smart about this stuff...And share what you learn on your journey- all of it- the good and the occasional bad. It helps grow the hobby, foster a viable movement, and helps your fellow hobbyists!
Stay studious. Stay thoughtful. Stay inquisitive. Stay creative. Stay engaged...
And Stay Wet.
Yes, I admit that we talk about some rather obscure topics around here. Yet, many of these topics are actually pretty well known, and even well-understood by science. We just haven't consciously applied them to our aquarium work...yet.
One of the topics that we talk about a lot are food webs. To me, these are fascinating, fundamental constructs which can truly have important influence on our aquariums.
So, what exactly is a food web?
A food web is defined by aquatic ecologists as a series of "trophic connections" (ie; feeding and nutritional resources in a given habitat) among various species in an aquatic community.
All food chains and webs have at least two or three of these trophic levels. Generally, there are a maximum of four trophic levels. Many consumers feed at more than one trophic level.
So, a trophic level in our case would go something like this: Leaf litter, bacteria/fungal growth, crustaceans...
In the wild aquatic habitats we love so much, food webs are vital to the organisms which live in them. They are an absolute model for ecological interdependencies and processes which encompass the relationship between the terrestrial and aquatic environments.
In many of the blackwater aquatic habitats that we're so obsessed with around here, like the Rio Negro, for example, studies by ecologists have determined that the main sources of autotrophic sources are the igapo, along with aquatic vegetation and various types of algae. (For reference, autotrophs are defined as organisms that produce complex organic compounds using carbon from simple substances, such as CO2, and using energy from light (photosynthesis) or inorganic chemical reactions.)
Hmm. examples would be phytoplankton!
Now, I was under the impression that phytoplankton was rather scarce in blackwater habitats. However, this indicates to scientists is that phytoplankton in blackwater trophic food webs might be more important than originally thought!
Now, lets get back to algae and macrophytes for a minute. Most of these life forms enter into food webs in the region in the form of...wait for it...detritus! Yup, both fine and course particular organic matter are a main source of these materials. I suppose this explains why heavy accumulations of detritus and algal growth in aquaria go hand in hand, right? Detritus is "fuel" for life forms of many kinds.
In Amazonian blackwater rivers, studies have determined that the aquatic insect abundance is rather low, with most species concentrated in leaf litter and wood debris, which are important habitats. Yet, here's how a food web looks in some blackwater habitats : Studies of blackwater fish assemblages indicated that many fishes feed primarily on burrowing midge larvae (chironomids, aka "Bloodworms" ) which feed mainly with organic matter derived from terrestrial plants!
And of course, allochtonous inputs (food items from outside of the ecosystem), like fruits, seeds, insects, and plant parts, are important food sources to many fishes. Many midwater characins consume fruits and seeds of terrestrial plants, as well as terrestrial insects.
Insects in general are really important to fishes in blackwater ecosystems. In fact, it's been concluded that the the first link in the food web during the flooding of forests is terrestrial arthropods, which provide a highly important primary food for many fishes.
These systems are so intimately tied to the surrounding terrestrial environment. Even the permanent rivers have a strong, very predictable "seasonality", which provides fruits, seeds, and other terrestrial-originated food resources for the fishes which reside in them. It's long been known by ecologists that rivers with predictable annual floods have a higher richness of fish species tied to this elevated rate of food produced by the surrounding forests.
And of course, fungal growths and bacterial biofilms are also extremely valuable as food sources for life forms at many levels, including fishes. The growth of these organisms is powered by...decomposing leaf litter!
Sounds familiar, huh?
So, how does a leaf break down? It's a multi-stage process which helps liberate its constituent compounds for use in the overall ecosystem. And one that is vital to the construction of a food web.
The first step in the process is known as leaching, in which nutrients and organic compounds, such as sugars, potassium, and amino acids dissolve into the water and move into the soil.The next phase is a form of fragmentation, in which various organisms, from termites (in the terrestrial forests) to aquatic insects and shrimps (in the flooded forests) physically break down the leaves into smaller pieces.
As the leaves become more fragmented, they provide more and more surfaces for bacteria and fungi to attach and grow upon, and more feeding opportunities for fishes!
Okay, okay, this is all very cool and hopefully, a bit interesting- but what are the implications for our aquariums? How can we apply lessons from wild aquatic habitats vis a vis food production to our tanks?
This is one of the most interesting aspects of a botanical-style aquarium: We have the opportunity to create an aquatic microcosm which provides not only unique aesthetics- it provides nutrient processing, and to some degree, a self-generating population of creatures with nutritional value for our fishes, on a more-or-less continuous basis.
Incorporating botanical materials in our aquariums for the purpose of creating the foundation for biological activity is the starting point. Leaves, seed pods, twigs and the like are not only "attachment points" for bacterial biofilms and fungal growths to colonize, they are physical location for the sequestration of the resulting detritus, which serves as a food source for many organisms, including our fishes.
Think about it this way: Every botanical, every leaf, every piece of wood, every substrate material that we utilize in our aquariums is a potential component of food production!
The initial setup of your botanical-style aquarium will rather easily accomplish the task of facilitating the growth of said biofilms and fungal growths. There isn't all that much we have to do as aquarists to facilitate this but to simply add these materials to our tanks, and allow the appearance of these organisms to happen.
You could add pure cultures of organisms such as Paramecium, Daphnia, species of copepods (like Cyclops), etc. to help "jump start" the process, and to add that "next trophic level" to your burgeoning food web.
In a perfect world, you'd allow the tank to "run in" for a few weeks, or even months if you could handle it, before adding your fishes- to really let these organisms establish themselves. And regardless of how you allow the "biome" of your tank to establish itself, don't go crazy "editing" the process by fanatically removing every trace of detritus or fragmented botanicals.
When you do that, you're removing vital "links" in the food chain, which also provide the basis for the microbiome of our aquariums, along with important nutrient processing.
So, to facilitate these aquarium food webs, we need to avoid going crazy with the siphon hose! Simple as that, really!
Yeah, the idea of embracing the production of natural food sources in our aquariums is elegant, remarkable, and really not all that surprising. They will virtually spontaneously arise in botanical-style aquariums almost as a matter of course, with us not having to do too much to facilitate it.
It's something that we as a hobby haven't really put a lot of energy in to over the years. I mean, we have spectacular prepared foods, and our understanding of our fishes' nutritional needs is better than ever.
Yet, there is something tantalizing to me about the idea of our fishes being able to supplement what we feed. In particular, fry of fishes being able to sustain themselves or supplement their diets with what is produced inside the habitat we've created in our tanks!
A true gift from Nature.
I think that we as botanical-style aquarium enthusiasts really have to get it into our heads that we are creating more than just an aesthetic display. We need to focus on the fact that we are creating functional microcosms for our fishes, complete with physical, environmental, and nutritional aspects.
Food production- supplementary or otherwise- is something that not only is possible in our tanks; it's inevitable.
I firmly believe that the idea of embracing the construction (or nurturing) of a "food web" within our aquariums goes hand-in-hand with the concept of the botanical-style aquarium. With the abundance of leaves and other botanical materials to "fuel" the fungal and microbial growth readily available, and the attentive husbandry and intellectual curiosity of the typical "tinter", the practical execution of such a concept is not too difficult to create.
We are truly positioned well to explore and further develop the concept of a "food web" in our own systems, and the potential benefits are enticing!
Work the web- in your own aquarium!
Stay curious. Stay observant. Stay creative. Stay diligent. Stay open-minded...
And Stay Wet.
Even with the exploding popularity of botanical-style aquariums, I still receive many questions from hobbyists unfamiliar with our practice, asking what the purpose or benefit is of utilizing these materials in our tanks. I find myself repeating the mantra that this is not purely an aesthetic statement.
Utilizing natural botanical materials in our aquariums is not an aquascaping style; rather, it's a methodology for creating and managing a biologically diverse closed aquatic ecosystem.
There is also something very different about the way that our fishes behave when they are living in an environment which has an abundance of natural materials present.
I know, it sounds a bit weird, but it's true! We receive lots of comments about this. It's sort of an "intangible" that comes with using them in our tanks. And I suppose it makes a lot of sense, as the fishes are utilizing them much as they do in their wild habitats, for shelter, grazing, and spawning.
Now sure, in a tank devoid of natural materials like botanicals, fishes will utilize whatever materials are available to shelter among, graze, and even spawn (hello, "spawning cones" and cracked flower pots!). Yet, there is a certain "something" that's different when you use botanicals. You can just see it.
Of course, with botanical materials, you have the added benefit that they are natural materials, consisting of substances like lignin, and they can impart other compounds stored in their tissues, such as tannin and humic substances, into the surrounding water column. And many fishes feed directly on the botanicals themselves, or remove "biocover" from their surfaces.
Yeah, think about it:
The texture and chemical composition of the botanicals' exteriors is really well-suited for the recruitment and growth of biofilms and fungal populations- important for the biological diversity and "operating system" of the aquarium, as we've talked about numerous times here. This is such an easily overlooked benefit of using natural materials in the aquarium.
And of course, as we know, terrestrial botanical materials, when submerged in water for extended periods of time, decompose. If there is one aspect of our botanical-style aquariums which fascinates me above almost anything else, it's the way they facilitate the natural processes of life- specifically, decomposition.
Decomposition is fundamental to the botanical style aquarium.
We use this term a lot around here...What, precisely does it mean?
de·com·po·si·tion- dēˌkämpəˈziSH(ə)n -the process by which organic substances are broken down into simpler organic matter.
A very apt descriptor, if you ask me!
We add leaves and botanicals to our aquariums, and over time, they start to soften, break up, and ultimately, decompose. Decomposition of leaves and botanicals not only liberates the substances contained within them (lignin, organic acids, and tannins, just to name a few) into the water- it serves to nourish bacteria, fungi, and other microorganisms and crustaceans, facilitating basic "food web" within the botanical-style aquarium, just like it does in Nature- if we allow it to!
PVC pipe sections, flower pots, and plastic plants can't do THAT!
Utilizing botanical materials and leaves in your tank, and leaving them in until they fully decompose is as much about your aesthetic preferences as it is long-term health of the aquarium.
It's a decision that each of us makes based on our tastes, management "style", and how much of a "mental shift" we've made into accepting the transient nature of materials in a botanical-style aquarium and its function. There really is no "right" or "wrong" answer here. It's all about how much you enjoy what happens in Nature versus what you can control in your tank. Nature will utilize them completely, as she does in the wild.
I tend to favor Nature, of course. But that's just me.
And of course, we can't ever lose sight of the fact that we're creating and adding to a closed aquatic ecosystem, and that our actions in how we manage our tanks must map to our ambitions, tastes, and the "regulations" that Nature imposes upon us.
Yes, anything that you add into your aquarium that begins to break down is bioload.
Everything that imparts proteins, organics, etc. into the water is something that you need to consider. However, it's always been my personal experience and opinion that, in an otherwise well-maintained aquarium, with regular attention to husbandry, stocking, and maintenance, the "burden" of botanicals in your water is surprisingly insignificant.
Even in test systems, where I intentionally "neglected" them by conducting sporadic water exchanges, once I hit my preferred "population" of botanicals (by buying them up gradually), I have never noticed significant phosphate or nitrate increases that could be attributed to their presence.
Understand that the process of decomposition is a fundamental, necessary function that occurs in our aquariums on a constant basis, and that botanicals are the "fuel" which drives this process. Realize that in the botanical-style aquarium, we are, on many levels, attempting to replicate the function of natural habitats- and botanical materials are just part of the equation.
And of course, these botanical materials not only offer unique natural aesthetics- they offer enrichment of the aquatic habitat through their release of tannins, humic acids, vitamins, etc. as they decompose- just as they do in Nature.
Leaves and such are simply not permanent additions to our 'scapes, and if we wish to enjoy them in their more "intact" forms, we will need to replace them as they start to break down. This is not a bad thing. It just requires us to "do some stuff" if we are expecting a specific aesthetic.
This is very much replicates the process which occur in Nature, doesn't it? Stuff like seed pods and leaves either remains "in situ" as part of the local habitat, or is pushed downstream by wind, current, etc. - and new materials continuously fall into the waters to replace the old ones.
Pretty much everything we do in a botanical-style blackwater aquarium has a "natural analog" to it!
Despite their impermanence, these materials function as diverse harbors of life, ranging from fungal and biofilm mats, to algae, to micro crustaceans and even epiphytic plants. Decomposing leaves, seed pods, and tree branches make up the substrate for a complex web of life which helps the fishes that we're so fascinated by flourish.
Intangibles? Perhaps. Yet, highly beneficial and consequential ones, indeed.
Stay persistent. Stay bold. Stay consistent. Stay observant...
And Stay Wet.