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.
A couple of days back, I was chatting with a fellow hobbyist who wanted to jump in to something a bit different within the aquarium hobby, but was afraid of the possible consequences-both socially and in his aquariums. He feared criticism from "them", and that just froze him. I felt bad that he was so afraid of criticism from others should he question the "status quo" within the hobby.
Perhaps my story might be helpful to you if you're afraid of such criticisms.
For generations, we've been told in the aquarium hobby that we need to be concerned about the appearance of all kinds of stuff in our tanks, like algae, detritus, and "biocover".
For some strange reason, we as a hobby group seems emphasize stuff like understanding some biological processes, like the nitrogen cycle, yet we've also been told to devote a lot of resources to siphoning, polishing, and scrubbing our tanks to near sterility.
It's a strange dichotomy.
I remember the first few botanical-style tanks I created, almost two decades ago now, would hit that phase early on when biofilms and fungal growths began to appear, and I'd hear my friends telling me, "Yeah, your tank is going to turn into a big pile of shit. Told you that you can't put that stuff in there."
Because that's what they've been told. The prevailing mindset in the hobby was that the appearance of these organisms was an indication of an unsuitable aquarium environment.
Anyone who's studied basic ecology and biology understands that the complete opposite is true. The appearance of these valuable life forms is an indicator that your aquatic environment is ideal to foster a healthy, diverse community of aquatic organisms, including fishes!
Exactly like in Nature.
I remember telling myself that this is what I knew was going to happen. I knew how biofilms and fungal growths appear on "undefended" surfaces, and that they are essentially harmless life forms, exploiting a favorable environment. I knew that fungi appear as they help break down leaves and botanicals. I knew that these are perfectly natural occurrences, and that they typically are transitory and self-limiting to some extent.
Normal for this type of aquarium approach. I knew that they would go away, but I also knew that there would be a period of time when the tank might look like a big pool of slimy shit. Or, rather, it'd look like a pile of slimy shit to those who weren't familiar with these life forms, how they grow, and how the natural aquatic habitats we love so much actually function and appear!
To reassure myself, I would stare for hours at underwater photos taken in the Amazon region, showing decaying leaves, biofilms,and fungi all over the leaf litter. I'd read the studies by researchers like Henderson and Walker, detailing the dynamics of leaf litter zones and how productive and unique they were.
I'd pour over my water quality tests, confirming for myself that everything was okay. It always was. And of course I would watch my fishes for any signs of distress...
I never saw them.
I knew that there wouldn't be any issues, because I created my aquariums with a solid embrace of basic aquatic biology; an understanding that an aquarium is not some sort of underwater art installation, but rather, a living, breathing microcosm of organisms which work together to create a biome..and that the appearance of the aquarium only tells a small part of the story.
I knew that this type of aquatic habitat could be replicated in the aquarium successfully. I realized that it would take understanding, trial and error, and acceptance that the aquariums I created would look fundamentally different than anything I had experienced before.
I knew I might face criticism, scrutiny, and even downright condemnation from some quarters for daring to do something different, and then for labeling what most found totally distasteful, or have been conditioned by "the hobby" for generations to fear, as simply "a routine part of the process."
It's what happens when you venture out into areas of the hobby which are a bit untested. Areas which embrace ideas, aesthetics, practices, and occurrences which have existed far out of the mainstream consciousness of the hobby for so long. Fears develop, naysayers emerge, and warnings are given.
Yet, all of this stuff- ALL of it- is completely normal, well understood and documented by science, and in reality, comprises the aquatic habitats which are so successful and beneficial for fishes in both Nature and the aquarium. We as a hobby have made scant little effort over the years to understand it. And once you commit yourself to studying, understanding, and embracing life on all levels, the world of natural, botanical-style aquariums and its untapped potential opens upon to you.
Mental shifts are required. Along with study, patience, time, and a willingness to look beyond hobby forums, aquarium literature, and aquascaping contests for information. A desire to roll up your sleeves, get in there, ignore the naysayers, and just DO.
Don't be afraid of things because they look different, or somehow contrary to what you've heard or been told by others is "not healthy" or somehow "dangerous." Now sure, you can't obey natural "laws" like the nitrogen cycle, understanding pH, etc.
You can, however, question things you've been told to avoid based on superficial explanations based upon aesthetics.
Stuff that makes you want to understand how life forms such as fungi, for example, arise, multiply, snd contribute to the biome of your aquarium.
Let's think about fungi for a minute...a "poster child" for the new way of embracing Nature as it is.
Fungi reproduce by releasing tiny spores that then germinate on new and hospitable surfaces (ie, pretty much anywhere they damn well please!). These aquatic fungi are involved in the decay of wood and leafy material. And of course, when you submerge terrestrial materials in water, growths of fungi tend to arise. Anyone who's ever "cured" a piece of wood for your aquarium can attest to this!
Fungi tend to colonize wood because it offers them a lot of surface area to thrive and live out their life cycle. And cellulose, hemicellulose, and lignin, the major components of wood and botanical materials, are degraded by fungi which posses enzymes that can digest these materials! Fungi are regarded by biologists to be the dominant organisms associated with decaying leaves in streams, so this gives you some idea as to why we see them in our aquariums, right?
And of course, fishes and invertebrates which live amongst and feed directly upon the fungi and decomposing leaves and botanicals contribute to the breakdown of these materials as well! Aquatic fungi can break down the leaf matrix and make the energy available to feeding animals in these habitats. And look at this little gem I found in my research:
"There is evidence that detritivores selectively feed on conditioned leaves, i.e. those previously colonized by fungi (Suberkropp, 1992; Graca, 1993). Fungi can alter the food quality and palatability of leaf detritus, aecting shredder growth rates. Animals that feed on a diet rich in fungi have higher growth rates and fecundity than those fed on poorly colonized leaves. Some shredders prefer to feed on leaves that are colonized by fungi, whereas others consume fungal mycelium selectively..."
"Conditioned" leaves, in this context, are those which have been previously colonized by fungi! They make the energy within the leaves and botanicals more available to higher organisms like fishes and invertebrates!
The aquatic fungi which will typically decompose leaf litter and wood are the group known as “aquatic hyphomycetes”. Another group of specialists, "aero-aquatic hyphomycetes," colonize submerged plant detritus in stagnant and slow- flowing waters, like shallow ponds, puddles, and flooded forest areas. Fungal communities differ between various environments, such as streams, shallow lakes and wetlands, deep lakes, and other habitats such as salt lakes and estuaries.
And we see them in our own tanks all the time, don't we? Sure, it's easy to get scared by this stuff...and surprisingly, it's even easier to exploit it as a food source for your animals! We just have to make that mental shift... As the expression goes, "when life gives you lemons, make lemonade!"
I knew when I started Tannin that I had to "walk the walk." I had to explain by showing my tanks, my work, and giving fellow hobbyists the information, advice, and support they needed in order to confidently set out on their own foray into this interesting hobby path.
I'm no hero. Not trying to portray myself as a visionary.
The point of sharing my personal experience is to show you that trying new stuff in the hobby does carry risk, fear, and challenge, but that you can and will persevere if you believe. If you push through. IF you don't fear setbacks, issues, criticisms from naysayers.
You have to try. In my case, the the idea of throwing various botanical items into aquariums is not my invention. It's not a totally new thing. People have done what I've done before. Maybe not as obsessively or thoroughly presented (and maybe they haven't built a business around the idea!), but it's been done many, many times.
The fact is, we can and should all take these kinds of journeys.
Stay the course. Don't be afraid. Open your mind. Study what is happening. Draw parallels to the natural aquatic ecosystems of the world. Look at this "evolution" process with wonder, awe, and courage.
And know that the pile of decomposing leaves, fungal growth, and detritus that you're looking at now is just a steppingstone on the journey to an aquarium which embrace nature in every conceivable way.
Stay brave. Stay curious. Stay diligent. Stay observant...
And Stay Wet.
We talk a lot about starting up and managing botanical-style aquariums. We have had numerous discussions about set up and the accompanying expectations of the early days in the life of the little ecosystems we've created. However, what about the long term..The really long term?
Like, how long can you maintain one of these aquariums?
Do they have an "expiration date? A point when the system no longer "grows" or thrives?
There is a term, sometimes used to describe the state of very old aquariums- "senescence." The definition is: "...the condition or process of deterioration with age." Well, that doesn't sound all that unusual, right? I mean, stuff ages, gets old, stops functioning well, and eventually expires...aquariums are no different, right?
Well, I don't think so.
Sometimes, this deterioration is referred to in the hobby by the charming name of "Old Tank Syndrome"
Now, on the surface, this makes some sense, right? I mean, if your tank has been set up for several years, environmental conditions will change over time. Among the many phenomenon brought up by proponents of this theory is the increase in nitrate levels. People who buy into "OTS" will tell you that nitrate levels will increase over time.
They'll tell you that phosphate, which typically comes into our tanks with food, will accumulate, resulting in excessive, perhaps rampant, algal growths. You know, the kind from which aquarium horror stories are made.
They will tell you that the pH of the aquarium will decline as a result of accumulating nitrate, with hydrogen ions utilizing all available buffers, resulting in a reduction of the pH below 6 (like, IS that a problem?), which supposedly results in the beneficial bacteria ceasing to convert ammonia into nitrite and nitrate and creating a buildup of toxic ammonia...
I mean, it's absolutely possible. We've talked about the potential cessation of the nitrogen cycle as we know it at low pH levels, and about the archaens which take over at these low pH levels. (That's a different "thing", though, and off topic ATM)
Of course, all of the bad things espoused by the OTS theorists can and will happen...If you never do any tank maintenance. If you simply abandon the idea of water exchanges, continue stocking and feeding your aquarium recklessly, and essentially abandon the basic tenants of aquarium husbandry.
The problem with this theory is that it assumes all aquarists are knuckleheads, refusing to perform water exchanges, while merrily going about their business of watching the pretty fishes swim. It seems to forecast some sort of inevitability that this will happen to every tank.
No way. Uh-uh. I call B.S. on this.
As someone who has kept all sorts of tanks (reef tanks, freshwater fish-only tanks, etc.) in operation for many years (my longest was 13 years, and botanical-style tanks going on 5 plus years), I can't buy into this idea. I mean, sure, if you don't set up a system properly in the first place, and then simply become lackadaisical about husbandry, of course your tank can decline.
But, here's the thing: It's not inevitable.
RULE OF THUMB: Do fucking maintenance, feed carefully, and don't overstock. This is not "rocket science!"
Rather than "Old Tank Syndrome"- a name which seems to imply that it's not our fault, and that it's like some unfortunate, random occurrence which befalls the unsuspecting-we should call it LAAP- "Lazy Ass Aquarists' Payback."
'Cause that's what it IS. It's entirely the fault of a lazy-ass aquarist. Preventable and avoidable.
Need more convincing that it's not some random "malady" that can strike any tank? That it's some "universal constant" which commonly occurs in all aquariums?
Think about the wild habitats which we attempt to model our aquariums after. Do these habitats decline over time for no reason? Generally, no. They will respond to environmental changes, like drought, pollution, sedimentation, etc. They will react to these environmental pressures or insults. They will evolve over time.
Now, sure, seasonal desiccation and such result in radical environmental shifts in the the aquatic environment and a definite "expiration date"- but you seldom hear of aquatic habitats declining and disappearing or becoming otherwise uninhabitable to fishes without some significant (often human-imposed) external pressures- like pollution, ash from fires or volcanoes, deliberate diversion or draining of the water source (think "Rio Xingu"), logging operations, climate change, etc.
Of course, our aquariums are closed ecosystems. However, the same natural laws which govern the nitrogen cycle or other aspects of the system's ecology in Nature apply to our aquariums. The big difference is that our tanks are almost completely dependent upon us as aquarists applying techniques which replicate some of the factors and processes which apply in Nature. Stuff like water exchanges, etc.
So if we keep up the nutrient export processes, don't radically overstock our systems, feed appropriately, maintain filters, and observe them over time, there is no reason why we couldn't maintain our aquariums indefinitely.
There is no "expiration date."
And the cool thing about botanical-style aquariums is that part of our very "technique" from day one is to facilitate the growth and reproduction of beneficial microfauna, like bacteria, fungal growths, etc., and to allow decomposition to occur to provide them feeding opportunities.What this does is help create a microbiome of organisms which, as we've said repeatedly, form the basis of the "operating system" of our tanks.
Each one of these life forms supporting, to some extent, those above...including our fishes.
So, yeah- botanical-style aquariums are "built" for the long run. Provided that we do our fair share of the work to support their ecology. Just because we add a lot of botanical material, allow decomposition, and tend to look on the resulting detritus favorably doesn't mean that these are "set-and-forget" systems, any more than it means they're particularly susceptible to all of the problems we discussed previously.
Common sense husbandry and observation are huge components of the botanical-style aquarium "equation."
As part of our regular husbandry routine, we keep the ecosystem "stocked" with fresh botanicals and leaves on a continuous basis, to replenish those which break down via decomposition. This is perfectly analogous to the processes of leaf drop and the influx of allochthonous materials from the surrounding terrestrial habitat which occur constantly in the wild aquatic habitats which we attempt to replicate.
We favor a "biology/ecology first" mindset.
Replenishing the botanical materials provides surface area and food for the numerous small organisms which support our systems. It also provides supplemental food for our fishes, as we've discussed previously. It helps recreate, on a very real level, the "food webs" which support the ecology of all aquatic ecosystems.
And it sets up botanical-style aquariums to be sustainable indefinitely.
Radical moves and "Spring Cleanings" are not only unnecessary, IMHO- they are potentially disruptive and counter-productive. Rather, it's about deliberate moves early on, to facilitate the emergence of this biome, and then steady, regular replenishment of botanical materials to nourish and sustain the ecosystem.
My belief is steeped in the mindset that you've created a little ecosystem, and that, if you start removing a significant source of someone's food (or for that matter, their home!), there is bound to be a net loss of biota...and this could lead to a disruption of the very biological processes that we aim to foster.
Okay, it's a theory...But I think I might be on to something, maybe? So, like here is my theory in more detail:
Simply look at the botanical-style aquarium (like any aquarium, of course) as a little "microcosm", with processes and life forms dependent upon each other for food, shelter, and other aspects of their existence. And, I really believe that the environment of this type of aquarium, because it relies on botanical materials (leaves, seed pods, etc.), is significantly influenced by the amount and composition of said material to "operate" successfully over time.
No expiration date.
Personally, I don't think that botanical-style aquariums are ever "finished", BTW. They simply continue to evolve over extended periods of time, just like the wild habitats that we attempt to replicate in our tanks do.
The continuous change, development, and evolution of aquatic habitats is a fascinating, compelling area to study- and to replicate in our aquaria. I'm convinced more than ever that the secrets that we learn by fostering and accepting Nature's processes and dynamics are the absolute key to everything that we do in the aquarium.
The idea that your aquarium environment simply deteriorates as a result of its very existence is, in my humble opinion, wrong, narrow-minded, and outdated thinking. (Other than that, it's completely correct!😆).
"Old Tank Syndrome" is a crock of shit, IMHO.
Aquariums only have an "expiration date" if we don't take care of them. Period. No more sugar coating this.
If we look at them assume sort of "static diorama" thing, requiring no real care, they definitely have an "expiration date"; a point where they are no longer sustainable. When we consider our aquariums to be tiny, closed ecosystems, subject to the same "rules" which govern the natural environments which we seek to replicate, the parallels are obvious. The possibilities open up. And the potential to unlock new techniques, ideas, and benefits for our fishes is very real and truly exciting!
I'm not entirely certain how this approach to aquariums, and this idea of fostering a microbiome within our tank and caring for it has become a sort of "revolutionary" or "counter-culture" sort of thing in the hobby, as many fellow hobbyists have told me that they feel it is.
Label it what you want, I think that, if we make the effort to understand the function of our tanks as much as we do the appearance, then it all starts making sense. If you look at an aquarium as you would a garden- an organic, living, evolving, growing entity- one which requires a bit of care on our part in order to thrive-then the idea of an "expiration date" or inevitable decline of the system becomes much less logical.
Rather, it's a continuous and indefinite process.
No "end point."
Much like a "road trip", the "destination" becomes less important than the journey. It's about the experiences gleaned along the way. Enjoyment of the developments, the process. In the botanical-style aquarium, it's truly about a dynamic and ever-changing system. Every stage holds fascination.
An aquatic display is not a static entity, and will continue to encompass life, death, and everything in between for as long as it's in existence. There is no expiration date for our aquariums, unless we select one.
Take great comfort in that simple truth.
Stay grateful. Stay enthralled. Stay observant. Stay patient. Stay dedicated...
And Stay Wet.
By now, this whole idea of adding botanical materials to our aquariums for the purpose of helping create the physical, biological, and chemical environment of our aquariums is becoming way more familiar. Yet, no matter how many times you've created a botanical-influenced natural aquarium, the experience seems new and somehow different.
Expectations are funny things, aren't they?
There is something very pure and evocative-even a bit "uncomfortable" about utilizing botanical materials in the aquarium. Selecting, preparing, and utilizing them is more than just a practice- it's an experience. A journey. One which we can all take- and all benefit from.
Right along with our fishes, of course!
And yeah, it can even be seen as a bit of a spiritual journey, too- leading to some form of enlightenment and education about Nature, from a totally unique perspective.
The energy and creativity that you bring with you on the journey tends to become amplified during the experience. As you work with botanicals in your aquariums, your mind takes you to different places; new ideas for how your aquarium's microcosm can evolve start flooding your mind. Every tank- like every hobbyist- is different- and different inspirations arise. We don’t want everyone walking away feeling the same thing, quite the opposite actually.
That uniqueness is a large part of the experience.
The experience is largely about discovery. And today's piece is a bit about some of the interesting discoveries- expectations, and revelations that we as a community have learned along the way during our experiences working with botanicals in our aquariums.
Our aquariums evolve, as do the materials within them. We've discussed this concept many times, but it's one that we keep coming back to.
If we think of an aquarium as we do a natural aquatic ecosystem, it's certainly realistic to assume that some of the materials in the ecosystem will change, re-distribute, or completely decompose over time.
Botanicals are not "forever" aquascaping materials. We consider them ephemeral in nature. They will soften, break down, and otherwise decompose over time. Some materials, like leaves- particularly Catappa and Guava, will break down more rapidly than others, and if you're like our friend Jeff Senske of Aquaiuim Design Group, and like the look of intact leaves versus partially decomposed ones, you'll want to replace them more frequently; typically on the order of every three weeks or so, in order to have more-or-less "intact" leaves in your tank.
On the other hand, if you're like me, and enjoy the more natural look that occurs as the leaves break down, just keep 'em in. You may need to remove some materials if you find fungal growth, biofilm, or other growth unsightly or otherwise untenable, or if material gets caught up in filter inlets, etc. However, "operational concerns" aside, and if you've made that "mental shift" and can tolerate the stuff decomposing, just let them be and enjoy!
Botanicals like the really hard seed pods (Sterculia Pods", "Cariniana Pods", "Afzelia Pods"), etc., can last for many, many months, and generally will soften on their interiors long before any decomposition occurs on the exterior "shell" of he botanical. In fact, they'll typically recruit biofilms, which almost seem to serve as a sort of "protective cover" that preserves them.
Often times, fishes like Plecos, Otocinculus catfish, loaches, Headstanders, and bottom-dwelling fishes will rasp or pick at the decomposing botanicals, which further speeds up the process. Others, like Caridina shrimp, Apistos, characins, and others, will pick at biofilms covering the interior and exterior of various botanicals, as well as at the microfauna which live among them, just as they do in Nature.
Sometimes, the fishes will use botanical materials for a spawning site.
We receive a lot of questions about which botanicals will "tint the water the darkest" or whatever. Cool questions. Well, here's the deal: Virtually all botanical materials will impact the color of the water. You'll find, as we have, that different materials will impart different colors into the water. It will typically be clear, but with a golden, brownish, or perhaps a slight reddish tint.
The degree of tint imparted will be determined by various factors, such as how much of the materials you use in your tank, how long they were boiled and soaked during the preparation process, if you're using activated carbon or other chemical filter media, and how much water movement is in your system. However, rest assured, almost any botanical materials you submerge in your tank will impart some color to the water.
Unfortunately, since botanicals are natural materials, there is no "recipe'; no formula with a set "X number of leaves/pods per ___ gallons of aquarium capacity", and you'll have to use your judgement as to how much is too much! It's as much of an "art" as it is a "science!"
Now, If you really dislike the tinted water, but love the look of the botanicals you can mitigate some of this by employing a lmuch onger "post-boil" soaking period- like over a week. Keep changing the water in your soaking container daily, which will help eliminate some of the accumulating organics, as well as to help you to determine the length of time that you need to keep soaking the botanicals to minimize the tint.
Of course, it's far easier to simply employ chemical filtration media, such as activated carbon, and/or synthetic adsorbents such as Seachem Purigen, to help eliminate a good portion of the excess discoloration within the display aquarium where the botanicals will ultimately "reside."
Another interesting phenomenon about "living with your botanicals" is that they will "redistribute" throughout the aquarium. They're being moved around by both current and the activities of fishes, as well as during our maintenance activities, etc. This is, not surprisingly, very similar to what occurs in Nature, where various events carry materials like seed pods, branches, leaves, etc. to various locales within a given body of water.
In our opinion, this movement of materials, along with the natural and "assisted" decomposition that occurs, will contribute to a surprisingly dynamic environment!
Your aquarium water may appear turbid at various times. We are pretty comfortable with this idea; however, some of you may not be. As bacteria act to break down botanical materials, they may impart a bit of "cloudiness" into the the water. Also, materials such as lignin and good old terrestrial soils/silt find their way into our tanks at times.
Some of these inputs, such as soils- are intentional! Others are the unintended by-product of the materials we use, The look is definitely different than what we as aquarists have been indoctrinated to accept as "normal." One of my good friends, and a botanical-style aquarium freak, calls this phenomenon "flavor"- and we see it as an ultimate expression of a truly natural-looking aquarium.
Yeah, the water itself becomes part of the attraction. The color, the "texture", and the clarity of the water are as engrossing and fascinating as the materials which affect it. It's something that you either love or simply hate...everyone who ventures into this method of aquarium keeping needs to make their own determination of wether or not they like it.
Need a bit more convincing to embrace the charm of the water itself in botanical-style aquariums?
Simply look at a natural underwater habitat, such as an igapo or flooded varzea grassland, and see for yourself the allure of these dynamic habitats, and how they're ripe for replication in the aquarium. You'll understand how the terrestrial materials impact the now aquatic environment- the function AND the aesthetic-fundamental to the philosophy of the botanical-style aquarium.
Speaking of the impact of terrestrial materials on the aquatic habitat- remember, too, that just like in Nature, if new botanicals are added into the aquarium as others break down, you'll have more-or-less continuous influx of materials to help provide enrichment to the aquarium environment. This type of "renewal" creates a very dynamic, ever-changing physical environment, while helping keep water chemistry changes to a minimum.
This is the perfect analog to the concept of "allochthonous input" which occurs in wild aquatic habitats- materials from outside the aquatic environment- such as the surrounding forest- entering and influencing the aquatic environment.
The fishes in your system may ultimately display many interesting behaviors, such as foraging activities, territorial defense, and even spawning, as a result of this regular influx of "fresh" aquatic botanicals. You could even get pretty creative, and attempt to replicate seasonal "wet" and "dry" times by adding new materials at specified times throughout the year...The possibilities here are as diverse and interesting as the range of materials that we have to play with!
Go into this with the expectation that you might get to experience an entirely different way of looking at aquariums- and the natural environments we try to replicate- and you'll never be disappointed.
It's all a part of your "life with botanicals"- an ever-changing, always interesting dynamic that can impact your fishes in so many beneficial ways.
Stay dedicated. Stay excited. Stay engaged. Stay resourceful...
And Stay Wet.
As we've all started to figure out by now, our botanical-influenced aquariums are a lot more of a little slice of Nature that you're recreating in your home then they are just a "pet-holding container."
The botanical-style aquarium is a microcosm which depends upon botanical materials to impact the environment.
This microcosm consists of a myriad of life format all levels and all sizes, ranging from our fishes, to small crustaceans, worms, and countless microorganisms. These little guys, the bacteria and Paramecium and the like, comprise what is known as the "microbiome" of our aquariums.
A "microbiome", by definition, is defined as "...a community of microorganisms (such as bacteria, fungi, and viruses) that inhabit a particular environment." (according to Merriam-Webster)
Now, sure, every aquarium has a microbiome to a certain extent:
We have the beneficial bacteria which facilitate the nitrogen cycle, and play an indespensible role in the function of our little worlds. The botanical-style aquarium is no different; in fact, this is where I start wondering...It's the place where my basic high school and college elective-course biology falls away, and you get into more complex aspects of aquatic ecology in aquariums.
Yet, it's important to at least understand this concept as it can relate to aquariums. It's worth doing a bit of research and pondering. It'll educate you, challenge you, and make you a better overall aquarist. In this little blog, we can't possibly cover every aspect of this- but we can touch on a few broad points that are really fascinating and impactful.
So much of this proces-and our understanding starts with...botanicals.
With botanicals breaking down in the aquarium as a result of the growth of fungi and microorganisms, I can't help but wonder if they perform, to some extent, a role in the management-or enhancement-of the nitrogen cycle.
Yeah, you understand the nitrogen cycle, right?
How do botanicals impact this process? Or, more specifically, the microorganisms that they serve?
In other words, does having a bunch of leaves and other botanical materials in the aquarium foster a larger population of these valuable organisms, capable of processing organics- thus creating a more stable, robust biological filtration capacity in the aquarium?
I believe that they do.
With a matrix of materials present, do the bacteria (and their biofilms- as we've discussed a number of times here) have not only a "substrate" upon which to attach and colonize, but an "on board" food source which they can utilize as needed?
Facultative bacteria, adaptable organisms which can use either dissolved oxygen or oxygen obtained from food materials such as sulfate or nitrate ions, would also be capable of switching to fermentationor anaerobic respiration if oxygen is absent.
Well, that's likely another topic for another time. Let's focus on some of the other more "practical" aspects of this "biome" thing.
Like...food production for our fishes.
In the case of our fave aquatic habitats, like streams, ponds, and inundated forests, epiphytes, like biofilms and fungal mats are abundant, and many fishes will spend large amounts of time foraging the "biocover" on tree trunks, branches, leaves, and other botanical materials.
The biocover consists of stuff like algae, biofilms, and fungi. It provides sustenance for a large number of fishes all types.
And of course, what happens in Nature also happens the aquarium- if we allow it to, right? And it can function in much the same way?
I am of the opinion that a botanical-style aquarium, complete with its decomposing leaves and seed pods, can serve as a sort of "buffet" for many fishes- even those who's primary food sources are known to be things like insects and worms and such. Detritus and the microorganisms within it can provide an excellent supplemental food source for our fishes!
Sustenence...from the microbiome.
It's well known that in many habitats, like inundated forests, etc., fishes will adjust their feeding strategies to utilize the available food sources at different times of the year, such as the "dry season", etc.
And it's also known that many fish fry feed actively on bacteria and fungi in these habitats...So I suggest once again that a botanical-style aquarium could be an excellent sort of "nursery" for many fish and shrimp species!
Again, it's that idea about the "functional aesthetics" of the, botanical-style aquariums. The idea which acknowledges the fact that the botanicals we use not only look cool, but they provide an important function (supplemental food production) as well. As we repeat constantly, the "look" is a collateral benefit of the function.
This is a profoundly important idea.
Perhaps arcane to some- but certainly not insignificant.
And of course, we've talked before about this "botanical nursery" concept- creating an aquarium for fish fry that has a large quantity of decomposing botanicals and leaves to foster the production of these materials, which serve as supplemental food for your fish fry. I have done this before myself and can attest to its viability. You fishes will have a constant supply of "natural" foods to supplement what you are feeding them in the early phases of their life.
Learn to make peace with your detritus! As always, look to the wild aquatic habitats of the world for an example of how this food source functions within the greater biome.
I'm fascinated by the "mental adjustments" that we need to make to accept the aesthetic and the processes of natural decay, fungal growth, the appearance of biofilms, and how these affect what's occurring in the aquarium. It's all a complex synergy of life and aesthetic.
And, in order to make the mental shifts which make this all work, we we have to accept Nature's input here.
Understand that, when we create a botanical-filled aquarium, not only do we have the opportunity to create an aquarium which differs significantly from those in years past- we have a unique window into the natural world and the role of these materials in the wild.
One thing that's very unique about the botanical-style approach is that we tend to accept the idea of decomposing materials accumulating in our systems. We understand that they act, to a certain extent, as "fuel" for the micro and macrofauna which reside in the aquarium, and that they perform this function as long as they are present in the system.
A profound mental shift...
And it's all about the microbiome. today's simple idea with enormous impact!
Stay curious. Stay thoughtful. Stay observant. Stay diligent...
And Stay Wet.
We so often discuss natural processes and features in our aquarium work.
There are a lot of interesting pieces of information that we can interpret from Nature when planning, creating, and operating our aquariums. The idea of replicating natural processes and occurrences in the confines of our aquariums, by simply setting up the conditions necessary for them to occur is fundamental to our botanical-oriented approach.
It goes without saying that there are implications for both the biology and chemistry of the aquatic habitats when leaves and other botanical materials enter them. Many of these are things that we as hobbyists observe every day in our aquariums!
Well, let's talk about our old friend and sometimes nemesis, biofilm.
A lab study I came upon found out that, when leaves are saturated in water, biofilm is at its peak when other nutrients (i.e.; nitrate, phosphate, etc.) tested at their lowest limits. Hmm...This is interesting to me, because it seems that, in our botanical-style aquariums, biofilms tend to occur early on, when one would assume that these compounds are at their highest concentrations, right? And biofilms are essentially the byproduct of bacterial colonization, meaning that there must be a lot of "food" for the bacteria at some point if there is a lot of biofilm, right?
Does this imply that the biofilms arrive on the scene and peak out really quickly; an indication that there is actually less nutrient in the water? Is the nutrient bound up in the biofilms? And when our fishes and other animals consume them, does this provide a significant source of sustenance for them? Can you have water with exceedingly low nutrient levels, while still having an abundant growth of biofilms?
Oh, and here is another interesting observation:
When leaves fall into streams, field studies have shown that their nitrogen content typically will increase. Why is this important? Scientists see this as evidence of microbial colonization, which is correlated by a measured increase in oxygen consumption. This is interesting to me, because the rare "disasters" that we see in our tanks (when we do see them, of course, which fortunately isn't very often at all)- are usually caused by the hobbyist adding a really large quantity of leaves at once, resulting in the fishes gasping at the surface- a sign of...oxygen depletion?
Makes sense, right?
These are interesting clues about the process of decomposition of leaves when they enter into our aquatic ecosystems. They have implications for our use of botanicals and the way we manage our aquariums. I think that the simple fact that pH and oxygen tend to go down quickly when leaves are initially submerged in pure water during lab tests gives us an idea as to what to expect.
A lot of the initial environmental changes will happen rather rapidly, and then stabilize over time. Which of course, leads me to conclude that the development of sufficient populations of organisms to process the incoming botanical load is a critical part of the establishment of our botanical-style aquariums.
Fungal populations are equally important in the process of breaking down leaves and botanical materials in water as are higher organisms, like insects and crustaceans, which function as "shredders." So the “shredders” – the animals which feed upon the materials that fall into the streams, process this stuff into what scientists call “fine particulate organic matter.”
And that's where fungi and other microorganisms make use of the leaves and materials, processing them into fine sediments. Allochthonous material can also include dissolved organic matter (DOM) carried into streams and re-distributed by water movement.
And the process happens surprisingly quickly, too.
In experiments carried out in tropical rainforests in Venezuela, decomposition rates were really fast, with 50% of leaf mass lost in less than 10 days! Interesting, but is it tremendously surprising to us as botanical-style aquarium enthusiasts? I mean, we see leaves begin to soften and break down in a matter of a couple of weeks- with complete breakdown happening typically in a month or so for many leaves. And biofilms, fungi, and algae are still found in our aquariums in significant quantities throughout the process.
So, what's this all mean? What are the implications for aquariums?
I think it means that we need to continue to foster the biological diversity of animals in our aquariums- embracing life at all levels- from bacteria to fungi to crustaceans to worms, and ultimately, our fishes...All of which form the basis of a closed ecosystem, and perhaps a "food web" of sorts for our little aquatic microcosms.
It's a very interesting concept- a fascinating field for research for aquarists, and we all have the opportunity to participate in this on a most intimate level by simply observing what's happening in our aquariums every day!
And facilitating this process is remarkably easy:
*Approach building an aquarium as if you are creating a biome.
*Foster the growth and development of a community of organisms at all levels.
*Allow these organisms to grow and multiply.
*Don't "edit" the growth of biofilms, fungal growths, and detritus.
By accepting and embracing these changes and little "evolutions", we're helping to create really great functional representations of the compelling wild systems we love so much!
Leaf litter beds, in particular, tend to evolve the most, as leaves are among the most "ephemeral" or transient of botanical materials we use in our aquariums. This is true in Nature, as well, as materials break down or are moved by currents, the structural dynamics of the features change.
We have to adapt a new mindset when aquascaping with leaves- that being, the 'scape will "evolve" on its own and change constantly...Other than our most basic hardscape aspects- rocks and driftwood- the leaves and such will not remain exactly where we place them.
To the "artistic perfectionist"-type of aquarist, this will be maddening.
To the aquarist who makes the mental shift and accepts this "wabi-sabi" idea (yeah, I'm sort of channeling Amano here...) the experience will be fascinating and enjoyable, with an ever-changing aquascape that will be far, far more "natural" than anything we could ever hope to conceive completely by ourselves.
It's not something to freak out about.
Rather, it's something to celebrate! Life, in all of it's diversity and beauty, still needs a stage upon which to perform...and you're helping provide it, even with this "remodeling" of your aquascape taking place daily. Stuff gets moved. Stuff gets covered in biofilm.
Stuff breaks down. In our aquairums, and in Nature.
Some people cannot fully grasp that.
Recently, I had a rather one-sided "discussion" (actually, it was mostly him attacking) with a "fanboy" of a certain style of aquarium keeping, who seemed to take a tremendous amount of pleasure in telling me that "our interpretation of Nature" and our embrace of decomposing leaves, biofilms, detritus, and such is a (and I quote) "...setback for the hobby of aquascaping..." (which, those of you who know me and my desire to provoke reactions, understand that I absolutely loved hearing!) and that "it's not possible to capture Nature" with our approach... (an ignorant, almost beyond stupid POV. I mean, WTF does "capture Nature" mean? Word salad.)
I was like, "C'mon, dude. Really? This is NOT a style of aquascaping!"
We repeat this theme a million times a year here: Nature is really not always clean and tidy. In fact- most of the time, it isn't. And if you buy into the head-scratching hobby narrative that every pristine "high-concept" contest aquarium is somehow what Nature "looks like", you're simply fooling yourself.
Sure, there are some really clear, sparkling habitats out there in the world, but they represent the exception, really.
Additionally, I'll go out on a limb and suggest that none of them have tidy rows of symmetrically trimmed, color- balanced plants, or neatly arranged rocks of related size and proportion. 😆
This is directed at a small, but vocal, and apparently misinformed crowd, but I can't stress this enough:
If you really want to understand the natural aquatic habitats of our fishes, some of you have to get out of the idealized aquascaping mindset for a bit and stop dissing everything that doesn't fit your idea of the way the world should be, and just accept the realities which Nature presents...
I am actually surprised we still get the occasional DM like this.
So I occasionally push back a bit.
Okay, I'm not bragging that our avant-garde love of dirty, often chaotic-looking aquariums makes us cooler than the "sterile glass pipe-loving aquascaping crowd. It's not really even a comparison, but its typically that crowd which hurls the insults at our approach, so...😆
However, I do want everyone to understand the degree to which we love the concept of Nature in it's most compelling form, and how strongly we feel that we, as a global community of hobbyists need to look beyond what's regularly presented to us as a "natural aquarium" and really give this stuff some thought. We CAN and SHOULD interpret natural aquatic features more literally in our aquairums.
Now, not all of Nature requires us to make extreme aesthetic preference shifts in order to love it.
Well, maybe not all. A lot of it, though.
It's a very different type of "aesthetic beauty" than we are used to. It's an elegant, remarkably complex microhabitat which is host to an enormous variety of life forms. And it's a radical departure from our normal interpretation of how a tank should look. It challenges us, not only aesthetically- it challenges us to appreciate the function it can provide if we let it.
"Functional aesthetics." Again.
Our "movement" believes in representing Nature as it exists in both form and function, without "editing" the very attributes of randomness and resulting function that make it so amazing.
And it all starts with understanding and facilitating natural processes without "editing" them to meet some ingrained aesthetic preferences.
Can you do that? Can you make that mental shift?
I hope so. We'd love to have you here!
Stay bold. Stay curious. Stay patient. Stay observant. Stay creative. Stay enthralled...
And Stay Wet.
Of all of the topics we cover here in "The Tint", the one we discuss the least (rather shockingly, I might add) is the fishes that we keep in our tanks! Yeahs, I talk more about fungi, sediments, decomposition, and leaf litter than I do about fishes...
And of course, when someone hit me up the other day and asked, "Scott, what are your favorite fishes for botanical-style aquariums?" I was like, "Well, shit- I never even covered that!" I mean, we should have covered that before. It's a cool topic. I'm kind of unsure why, actually.
Probably because most of the articles on this topic are kind of...oh, crap, I'll say it- just boring. Ever read one of those "Top 10" listicle thingys about fishes? They usually-well, suck. Harsh, but they're kind of boring, IMHO. I mean, they talk about the size of the fish, what it eats, and what size tank you can keep it in. I mean, helpful, but..I dunno. Boring. Stuff you can pretty much find in any aquarium-related reference. You don't come here for that, I hope... So, we'll try to cover these fishes from "a slightly different perspective", as I like to say.
So, let's hit that topic today! Okay, let's hit some of it today...my list is longer than my patience to discuss them all in one piece! And I'll try my best not to do it the boring way...
Oh, damn, I might have a bunch of fishes...but I don't think I'm gonna cover all of them today...
Give me a break- it's a start, right?
Now, here's the thing- you'll find that my fish choices are as much based upon the habitats that they come from as they are about the fishes themselves..
Okay, so let's get this party started...
In no particular order ( well, maybe in a sort of order..):
Sailfin Characin (Crenuchus spilurus)
We've all had that ONE fish which just sort of occupies a place in our hearts and minds- a fish that-for whatever reason- bites you and never lets go, right? I think that every serious aquarist has at least one such a fish..
Of course, it's also about the habitat which this fish lives in that's kept me under its spell for so long...
As a lover of leaf-litter in our natural, botanical-style aquariums, I am fascinated not only by this unique ecological niche, but by the organisms which inhabit it. I've went on and on and spoken at length about many of the microorganisms, fungi, insects, and crustaceans which add to the diversity of this environment. And of course, we've looked at some of the fishes which live there, too! Perhaps not enough, actually...
One of my all-time favorite fishes- and my absolute favorite characin is none other than the amazing "Sailfin Tetra", Crenuchus spilurus! This is a truly awesome fish- not only is it attractive and morphologically cool-looking, it has a great demeanor and behaviors which separate it from almost every other characin out there!
I first fell for this fish as a kid, when I saw a cool pic of it in my dad's well-worn copy of William T. Innes' classic book, Exotic Aquarium Fishes. The book that pretty much assured me from toddler days that I'd be a fish geek. I obsessed over the book before I could even read...
I was hooked from the start with Crenuchus, especially when reading about the romantic etymology of the name! And it just seemed so "mysterious" and unattainable, even in the 1930's...well, especially back in the 1930's, but it seemed downright exotic! To this day, it's one you just don't see too much of in the hobby. And then, tying it together with my love of those leaf-litter-strewn habitats, it was a combo which I couldn't resist!
I never got this fish out of my system, and it took me like 30-plus years of being a fish geek to find this fish in real life. And, you know that I jumped at the chance..It was so worth the wait!
It's almost "cichlid-like" in behavior: Intelligent, interactive, and endearing. It has social behaviors which will entertain and fascinate those who are fortunate enough to keep it.
Now, I admit, it's definitely NOT the most colorful characin on the planet. But there is more than this fish than meets the eye.
It all starts with its most intriguing name...
The Latin root of the genus Crenuchus means "Guardian of The Spring"- a really cool, even romantic-sounding name which evokes imagery-and questions! Does it mean the "protector" of a body of water, or some honorary homage to everyone's favorite season? Not sure, but you must agree that the name is pretty cool! In greek, it's krenoychos -"The God of running waters."
Yeah. That's the shit. I mean, do Latin names get any cooler than that?
The Crenuchidae (South American Darters) is a really interesting family of fishes, and includes 93 species in 12 genera throughout the Amazon region. Most crenuchids are- well, how do we put it delicately- "chromatically challenged" ( ie; grey-black-brown) fishes, which tend to lie in wait near the substrate (typically leaf litter or aggregations of branches), feeding on insects and micro invertebrates. And the genus Crenuchus consists of just one species, our pal Crenuchus spilurus, a fish which shares habits and a body shape that are more commonly associated with Cyprinids and...cichlids!
That's just weird.
Now, the relatively subdued coloration serves a purpose, of course. These fishes live among leaf litter, root tangles, and botanical debris..in tinted water...which demand (if you don't want to be food for bigger fishes and birds) some ability to camouflage yourself effectively.
The Sailfin is an exception to the "drab" thing, and it's remarkably attractive for a very "simple" benthic-living fish. Sure, on the surface, it's not the most exciting fish out there, especially when it's a juvenile...but it's a fish that you need to be patient with; a fish to search for, collect, hold onto, and enjoy as it matures and grows. As the fish matures, in true "ugly duckling"🐥 style, it literally "blossoms" into a far more attractive fish.
The males have an extended dorsal and anal fin, and are larger and more colorful than females. Yes, colorful is relative here, but when you see a group- you'll notice the sexual dimorphism right away, even among juveniles.
Individuals spend a lot of their time sheltered under dead leaves, branches, roots, and aquatic plants. They tend to "hover", and don't dart about like your typical Tetra would. In fact, their behavior reminds me of the Dartfishes of the marine aquarium world...They sort of sit and flick their fins, often moving in slow, deliberate motions. Communication? Perhaps.
The Sailfin feeds during the daylight hours, and spends much of its day sheltering under branches, leaves, and root tangles, and is a mid-water feeder, consuming particulate organic matter, such as aquatic invertebrates, insects, bits of flowers, and fruits- the cool food items from outside of the aquatic environment that form what ecologists call allochthonous input-materials from outside of the aquatic habitat, which are abundant in the terrestrial habitats surrounding the aquatic ones which we love to model our aquariums after.
Tucano Tetra (Tucanoichthys tucano)
You all know by now that my philosophy is to study and understand the environments from which our fishes come, and to replicate them in function and form as best as possible. It doesn't always mean exactly- but it's definitely NOT forcing them to adapt to our "local tap water "conditions without any attempt to modify them.
I have a very current "case study" of my own that sort of reflects the execution of my philosophy.
As many of you know, I've had a long obsession with the idea of root tangles and submerged accumulations of leaves, branches, and seed pods. I love the silty, sedimented substrates and the intricate interplay of terrestrial plant roots with the aquatic environment.
I was doing a geeky "deep dive" into this type of habitat in Amazonia one evening, and stumbled upon this gem from a scientific paper by J. Gery and U. Romer in 1997:
"The brook, 80-200cm wide, 50-100 cm deep near the end of the dry season (the level was still dropping at the rate of 20cm a day), runs rather swiftly in a dense forest, with Ficus trees and Leopoldina palms...in the water as dominant plants. Dead wood. mostly prickly trunks of palms, are lying in the water, usually covered with Ficus leaves, which also cover the bottom with a layer 50-100cm thick. No submerse plants. Only the branches and roots of emerge plants provide shelter for aquatic organisms.
The following data were gathered by the Junior author Feb 21, 1994 at 11:00AM: Clear with blackwater influence, extremely acid. Current 0.5-1 mv/sec. Temp.: Air 29C, water 24C at more than 50cm depth... The fish fauna seems quite poor in species. Only 6 species were collected I the brook, including Tucanoichthys tucano: Two cichlids, Nannacara adoketa, and Crenicichla sp., one catfish, a doradid Amblydoras sp.; and an as yet unidentified Rivulus, abundant; the only other characoid, probably syncopic, was Poecilocharax weitzmani."
Yeah, it turned out to be the ichthyological description of the little "Tucano Tetra", Tucanoichthys tucano, and was a treasure trove of data on both the fish and its habitat. I was taken by the decidedly "aquarium reproducible" characteristics of the habitat, both in terms of its physical size and its structure.
Boom! I was hooked.
I needed to replicate this habitat! And how could I not love this little fish? I even had a little aquarium that I had been dying to work with for a while.
It must have been "ordained" by the universe, right?
Now, I admit, I wasn't interested in, or able to safely lower the pH down to 4.3 ( which was one of the readings taken at the locale), and hold it there, but I could get the "low sixes" nailed easily! Sure, one could logically call me a sort of hypocrite, because I'm immediately conceding that I won't do 4.3, and I suppose that could be warranted...
However, there is a far cry between creating 6.2pH for my tank, which is easy to obtain and maintain for me, and "force-fitting" fishes to adapt to our 8.4pH Los Angeles tap water!
And of course, with me essentially trashing the idea of executing a hardcore 100% replication of such a specific locale, the idea was essentially to mimic the appearance and function of such an igarape habitat, replete with lots of roots and leaf litter.
And the idea of executing it in a nano-sized aquarium made the entire project more immediately attainable and a bit less daunting. I wanted to see if I could pull off a compelling biotope-inspired aquairum on a small scale.
That's where my real interest was.
So, even the "create the proper conditions for the fish instead of forcing them to adapt to what's easiest for us" philosophy can be nuanced! And it should! I don't want to mess with strong acids at this time. It's doable...a number of hobbyists have successfully. However, for the purposes of my experiment, I decided to happily abstain for now, lol.
And without flogging a dead horse, as the horrible expression goes, I think I nailed many of the physical attributes of the habitat of this fish. By utilizing natural materials, such as roots, which are representative of those found in the fish's habitat, as well as the use of Ficus and other small leaves as the "litter" in the tank, I think we created a cool biotope-inspired display for these little guys!
And man, I love this tank!
Being able to pull off many aspects of the look, feel and function of the natural habitat of the fish was a really rewarding experience. A real "case study" for my philosophy of fish selection and stocking.
Green Neon Tetra (Paracheirodon simulans)
Everyone knows the Neon Tetra, Paracheirodon inessi. It's a strong candidate for the title of "Official fish of the Aquarium Hobby!" Of course, there other members of the genus Paracheirodon which hobbyists have become enamored with, such as the diminutive, yet equally alluring P. simulans, the "Green Neon Tetra." Topping out at around 3/4" (about 2cm) in length, it's certainly deserving of the hobby label of "nano fish!"
You can keep these little guys in nice -sized aggregations..I wouldn't necessarily call them "schools", because, as our friend Ivan Mikolji beautifully observes, "In an aquarium P. simulans seem to be all over the place, each one going wherever it pleases and turning greener than when they are in the wild."
This cool little fish is one of my fave of what I call "Petit Tetras." Hailing from remote regions in the Upper Rio Negro and Orinoco regions of Brazil and Colombia, this fish is a real showstopper! According to ichthyologist Jacques Gery, the type locality of this fish is the Rio Jufaris, a small tributary of the Rio Negro in Amazonas State.
One of the rather cool highlights of this fish is that it is found exclusively in blackwater habitats. Specifically, they are known to occur in habitats called "Palm Swamps"( locally known as "campos") in the middle Rio Negro. These are pretty cool shallow water environments! Interestingly, P. simulans doesn't migrate out of these shallow water habitats (less romantically called "woody herbaceous campinas" by aquatic ecologists) like the Neon Tetra (P. axelrodi) does. It stays to these habitats for its entire lifespan.
These "campo" habitats are essentially large depressions which do not drain easily because of the elevated water table and the presence of a soil structure, created by our fave soil, hydromorphic podzol! "Hydromorphic" refers to s soil having characteristics that are developed when there is excess water present all or part of the time.
(Image by G. Durigan)
So, if you really want to get hardcore about recreating this habitat, you'd use immersion-tolerant terrestrial plants, such as Spathanthus unilateralis, Everardia montana, Scleria microcarpa, and small patches of shrubs such as Macairea viscosa, Tococa sp. and Macrosamanea simabifoli. And grasses, like Trachypogon.
Of course, our fave palm, Mauritia flexuosa and its common companion, Bactris campestris round out the native vegetation. Now, the big question is, can you find any of these plants? Perhaps...More likely, you could find substitutes.
Just Google that shit! Tons to learn about those plants!
These habitats are typically choked with roots and plant parts, and the bottom is covered with leaves and fallen palm fronds...This is right up our alley, right?
Of course, if you really want to be a full-on "baller" and replicate the natural habitat of these fishes as accurately as possible, it helps to have some information to go on! So, here are the environmental parameters from these "campo" habitats based on a couple of studies I found:
The dissolved oxygen levels average around 2.1 mg/l, and a pH ranging from 4.7-4.3. KH values are typically less than 20mg/L, and the GH generally less than 10mg/L. The conductivity is pretty low.
The water depth in these habitats, based on one study I encountered, ranged from as shallow as about 6 inches (15cm) to about 27 inches (67cm) on the deeper range. The average depth in the study was about 15" (38cm). This is pretty cool for us hobbyists, right? Shallow! I mean, we can utilize all sorts of aquariums and accurately recreate the depth of the habitats which P. simulans comes from!
We often read in aquarium literature that P. simulans needs fairly high water temperatures, and the field studies I found for this fish this confirm this.
Average daily minimum water temperature of P. simulans habitats in the middle Rio Negro was about 79.7 F (26.5 C) between September and February (the end of the rainy season and part of the dry season). The average daily maximum water temperature during the same period averaged about 81 degrees F (27.7 C). Temperatures as low as 76 degrees' (24.6 C) and as high as 95 degrees F (35.2 C) were tolerated by P. simulans with no mortality noted by the researchers.
Bottom line, you biotope purists? Keep the temperature between 79-81 degrees F (approx. 26 C-27C).
Researchers have postulated that a thermal tolerance to high water temperatures may have developed in P. simulans as these shallow "campos" became its only real aquatic habitat.
The fish preys upon that beloved catchall of "micro crustaceans" and insect larvae as its exclusive diet. Specifically, small aquatic annelids, such as larvae of Chironomidae (hey, that's the "Blood Worm!") which are also found among the substratum, the leaves and branches.
Now, if you're wondering what would be good foods to represent this fish's natural diet, you can't go wrong with stuff like Daphnia and other copepods. Small stuff makes the most sense, because of the small size of the fish and its mouthparts.
This fish would be a great candidate for an "Urban Igapo" style aquarium, in which rich soil, reminiscent of the podzols found in this habitat is use, along with terrestrial vegetation. You could do a pretty accurate representation of this habitat utilizing these techniques and substrates, and simply forgoing the wet/dry "seasonal cycles" in your management of the system.
There are a lot of possibilities here.
One of the most enjoyable and effective approaches I've taken to keeping this fish was a "leaf litter only" system (which we've written about extensively here. Not only did it provide many of the characteristics of the wild habitat (leaves, warm water temperatures, minimal water movement, and soft, acidic water).
So, maybe you've noticed a pattern to my love of certain fishes...so much is based upon the habitats that they come from. My love for the fishes was amplified when I studied and learned more about the unique habitats from which each of these fishes come. The idea of recreating various aspects of the habitat as the basis for working with these fishes is irresistible to me!
Diptail or Brown Pencilfish (Nanostomus eques)
This one really should have been the top choice if I were doing it in order. I LOVE everything about this fish. Well, almost everything.
Honestly, if a fish could earn the moniker "cool", this little guy would be it. It's absolutely not an overstatement to declare that these Pencilfishes have distinct personalities! They're not "mindless-drone, stupid schooling fishes", like some of the Tetras. (Sorry, my homies...Love ya' lots, but alas- you have no individual personalities...😂)
They are proud members of the family family Lebiasinidae. It was first described in 1876 by the legendary ichthyologist, Franz Steindachner. In fact, it was one of the first members of the genus Nanostomus to be discovered and described by science.
Cool, but that's not my main reason for loving this fish. There's a bunch of unique aspects to this fish's behavior which I find enormously compelling.
The Latin name of the species, eques, means "knight", "horseman", or "rider", in reference to this species’ unique oblique swimming angle.
Ah, that "oblique swimming angle" thing. Yeah, they swim at an angle of about 45 degrees facing upwards. This angle is thought to give them an advantage in feeding. They see insects and such that fall from overhanging vegetation better than their horizontally-oriented buddies do. They get more food that way. Simple.
(Image by Fajoe, used under CC BY-SA 3.0)
What I really love about these fish is that they are incredibly curious and obviously intelligent, checking out just about anything which goes on in their aquarium. You get the feeling when observing them that they are acutely aware of their surroundings, and once acclimated, are pretty much fearless. A fellow hobbyist once told me she thinks they're the freshwater equivalent of Pipefish...and that sounds about right..I agree with that 100%!
They're sociable, incredibly "chill" fish. Now, the thing about their ability to adeptly feed on allochthonous input into the aquatic environment makes them easy to feed. And it also gives you some clues as to the habitats they come from. Places where the food comes from the surrounding terrestrial environment.
Foods from the surrounding environment, such as flowers, fruits, terrestrial insects, etc. These are extremely important foods for many fish species that live in these habitats. We mimic this process when we feed our fishes prepared foods, as stuff literally "rains from the sky!" Now, I think that what we feed to our fishes directly in this fashion is equally as important as how it's fed.
The environments which provide this food abundance also provide lots of opportunities to replicate in our aquariums. I love that about this fish. They come from really cool, really inspiring habitats.
They are also really adept at picking on epiphytic materials in their botanical-style aquariums. It's an observation I've made many times with these fish.
Yeah, they seem to spend a large amount of time picking at biofilm and other material adhering to botanicals, and specifically, wood. They engage in this activity almost constantly throughout the day (between feedings, of course!). I am convinced that they are likely not specifically targeting the biofilm directly; rather, I think that they're looking for tiny crustaceans and other life forms that live in the matrix.
Nonetheless, their picking distrubs the films and puts it into suspension, where it can more easily be removed by filtration. This was an unexpected "plus" of this most beloved group of fishes. Now, I must warn you, biofilm haters- you shouldn't even consider Pencilfishes as a biofilm "control mechanism", but I suppose that to you heathens, the "collateral benefit" is nice.
They are very aware, very adept feeders...Always ready to pounce.
What's the thing I don't like about these fish?
Oh, they can be a bit skittish. Like, chill as they are, "stuff" just freaks them out.
They will, for seemingly no reason, launch themselves out of your open-top aquarium (well, those are the only types I keep...) with tremendous agility-sometimes landing a few inches away in the tank...Other times, completely leaving the tank, and well- usually this results in a very dried-out Pencilfish!
I guess the oblique swimming angle facilitates them reaching "escape velocity" rapidly. You get the feeling that they're always in "standby for launch!" mode. Like, full-on "defcon-5" mode.
Maybe, because they're always looking UP- the slightest disturbance from BELOW triggers a launch. I don't know, but it's as good a theory as any. And a 3-inch launch gets you away from a potential predator. A 6-inch launch lands you on the floor... Damn, a good adaptation for protection, this "launching" thing. But, like, who really wants to eat a Pencilfish, right? I guess the Pencilfish don't know that...They just jump. Millenia of genetic programming can't be overcome easily!
It sucks, but it's the downside to keeping them in open-top tanks. Lots of twisted branches and even floating plants DO help limit some of this "carpet surfing" behavior, but it's not a 100% perfect solution. I admit, These guys have, in the past played a central role in some of those "And then there were none" disappearing fish sagas that I've experienced over the years.
So, if you can keep them in a low- traffic area, employ lots of branches, and maybe some floating plants...maybe you'll avoid this.
I mean, these methods also occasionally work with Hatchetfishes...another fave of mine, but almost too suicidal, even for me. And that's why they are not in my top 10 list, if you're wondering..
Okay, I could probably do a top 10, or even a dozen- fave fishes, but I'd be writing all day on this topic. Honorable mention- The Checkerboard Cichlid (Dicrossus filamentosus)... My "go-to" cichlid for botanical-style tanks...I love them- even over Apistos...And, as one of my friends told me, "Of course you do Scott- they're fucking brown!"
Damn, my friends really know me well, huh?
Just try them in your next botanical-style aquarium. You won't regret it. Maybe we'll deep dive in the "Fellman style" on these guys next time...
Okay that's a start... I think I can safely employ the great line used by one of the aquarium hobby's great saltwater fish experts, Scott Michael, who, upon discussing such-and-such a fish would simply declare in a deadpan manner, "If you don't keep these fish, you're stupid.."
How can you argue with THAT kind of assertion? I totally relate to that. Well, shit- you asked me what my faves are...you knew I'd have some strong feelings about them, huh? 😆
Anyhow, I hope this little start gives you a look into the unorthodox way I think about the fish I select for my aquariums: So much of it is about studying a habitat I love, and then researching what fishes are found in it- and why. Then, creating the habitat for them. Like, "habitat-first." Totally works for me.
I hope it works for you too!
Until Next time...
Stay thoughtful. Stay curious. Stay bold. Stay diligent...
And Stay Wet.