Husbandry, process, observation- and consistency. Botanical-style aquariums in the long term...

We've talked so much about the idea of establishing a botanical-style aquarium (blackwater, brackish, or otherwise), from both a conceptual and procedural standpoint, that it's probably no longer a romantic and mysterious thing like it was only a few years ago. To many of us, it's become part of our aquarium hobby repertoire- a knowledge and "skill set" that we incorporate into our broader hobby experience.

Yet, I've probably not talked as much about the long-term maintenance and husbandry of these types of systems, and that's a huge part of this game, right?


We receive a lot of questions about what sort of ongoing maintenance procedures are necessary, and what sort of challenges you face, longer-term, with these tanks...We could probably write many blog posts about this interesting topic (and we will!), but an initial "quick hit" today will hopefully jump-start the discussion! (oh, and maybe answer some questions along the way!)

As we've talked about before, for the longest time, there seemed to have been a perception among the mainstream hobby that blackwater aquariums were delicate, tricky-to-maintain systems, fraught with potential disaster; a soft-water, acidic environment which could slip precipitously into some sort of environmental "free fall" without warning.

And there was the matter of that "dark brown water..."

Not only was the tinted water considered "the whole distinction" between these types of systems and more "conventional" aquariums, it was cause for fear, misunderstanding, and "myths."

Happily, this perception seems to be eroding, as a new generation of aquarists (hey, that's YOU guys!) has taken the torch and ran with it, taking a slightly different approach- and a vastly different attitude- and is perfecting the techniques required to maintain blackwater/botanical-style aquariums for the long term.

And the "long term" is where my interest lies.

The longest I've personally maintained such a system has been about 5.5 years, and the only reason I broke down that aquarium was because of a home remodel that required the removal of everything from the space in which the aquarium was located. I set it up again shortly after the work was completed. The reality, though, is that I could have kept this system going indefinitely. 

As most of you who work with these aquariums know, the key to long-term success with them is to go slowly, deploying massive amounts of patience, common-sense husbandry, monitoring of environmental parameters, and careful stocking management. Not really much different from what you'd need to do to successfully maintain ANY type of aquarium for the long haul.

Yeah, real "news flash" there, right?

So, it all starts with the way these tanks "run in", and that will sort of "set the tone" for the care and long-term maintenance involved.

First off, one of the things that we all experience with these types of systems is an initial burst of  tannins, which likely will provide a significant amount of visible "tint" to the water. If you're not using activated carbon or some other filtration media, this tint will be more pronounced and likely last longer than if you're actively removing it with these materials! And, if you use too much carbon, you'll be one of those people who emails me with a starting line like, "...and I added an entire package of catappa leaves and my water is barely tinted..."

You might also experience a bit of initial cloudiness or turbidity...this could either be physical dust or other materials released from the tissues botanicals, or even a burst of bacteria/microorganisms. Not really sure, but it usually passes quickly with minimal, if any intervention on your part. Oh, and not everyone experiences this...often this is a phenomenon which seems to happen in brand new it might not even be directly attributable to the presence of the botanicals (well, at least not 100%). Could be the sand, or other dust/dirt from the other hardscape materials or the tank itself.

Oh, and the reality is that in a tank with lots of botanical materials, the water may not always be "crystal clear." I mean, sure it'll be clear- as in, you can see across it- but it might have a sort of "soupy" look to it. This is for the very reasons stated above. Mental shifts required...

So, that being said...what happens next?

Well, typically, as most of you who've played with this stuff know, the botanicals will begin to soften and break down over a period of several weeks. Botanical materials are the very definition of the word "ephemeral." Nothing lasts forever, and botanicals are no exception! Pretty much everything we utilize- from Guava leaves to Melostoma roots- starts to soften and break down over time. Most of these materials should be viewed as "consumables"- meaning that you'll need to replace them over time.

As we've discussed ad nauseum, you have the option to leave 'em in as they break down, or remove them (whatever your aesthetic sensibilities tell you to do!). Many "Tinters" have been leaving their botanicals in until completely decomposed, utilizing them as almost some sort of botanical "mulch", particularly in planted aquariums, and have reported excellent results. As we work more and more on substrates, I think we will see more and more hobbyists leaving the materials in to fully decompose.

Oh, and sure, botanicals  will go through that "biofilm phase" before ultimately breaking down, and you'll have many opportunities to remove them...Or, in the case of most hobbyists these days- add new materials as the old ones break down...completely analogous to natural "leaf drop!"

Now, this idea of "leaving stuff in" always seems to get people "riled up!"

I have never had any negative side effects that we could attribute to leaving botanicals to completely break down in an otherwise healthy, well-managed aquarium.

Many, many users (present company included) see no detectable increases in nitrate or phosphate as a result of this practice. Of course, this has prompted me to postulate that perhaps they form a sort of natural "biological filtration media" and actually foster some dentritifcation, etc. I have no scientific evidence to back up this theory, of course (like most of my theories, lol), other than my results, but I think there might be a grain of truth here!

Oh, speaking of "grains"- one of the "bummers" of botanical aquarium keeping is that you will likely have to clean/replace prefilters, sponges, micron socks, and filter pads more frequently. Just like in nature, as the botanicals (leaves, in particular) begin to break down, you'll see some of the material suspended in the water column from time to time, and the "bits and pieces" which get pulled into your filter will definitely slow down the flow over time. The best solution, IMHO, is to simply change prefilters frequently and clean pumps/powerheads/glassware regularly as part of your weekly maintenance regimen.

And of course...this is the elegant segue into the part about your "weekly maintenance regimen", right?

Well, here's my thought on this: Do "whatever floats your boat", as they say. If you're a bi-weekly-type of tank maintenance person, do that. If you're a once-a-month kind of person...Well, you might want to re-examine that! LOL. Botanical-style blackwater tanks, although remarkably stable once up and running, really aren't true "set-and-forget" systems, IMHO.

You'll want to at least take a weekly or bi-weekly assessment on their performance and overall condition. Now, far be it from me to tell YOU- the experienced aquarist-how to run your tanks. However, I'm just sort of giving you a broad-based recommendation based upon my experiences and those of many others over the years with these types of systems. You need to decide what works best for you- and your animals, of course...

Now, remember, you're dealing with a tank filled with decomposing botanical materials. Good overall husbandry is necessary to keep your tank stable and healthy- and that includes the dreaded (by many, that is) regular water exchanges. As we pointed out, at the very least, you'll likely be cleaning and/or replacing pre filter media as part of your routine, and that's typically a weekly-to bi-weekly thing.  

Just sort of "goes with the territory" here.

During water exchanges, I typically will siphon out any debris which have lodged where I don't want 'em (like on the leaves of that nice Amazon Sword Plant right up front, or whatever), but for the most part, I'm merely siphoning water from down low in the water column. I'm a sort of "leave 'em alone as they decompose" kind-of-guy.

And I'm not going to go into all the nuances of water preparation, etc. today. I use straight-up, non-remineralized RO/DI water and have for decades in my tanks, and that freaks lots of people out, too. You likely have your ways and they work for you. If you want to hear my "methods" some time, just DM me on Facebook or whatever and we can discuss. It's not really rocket science or anything, but everyone has their own techniques.

And of course, regular water testing is important, too. 

Not just for the information you'll gain about your aquarium and it's trends. It's important because we, as proponents of the natural, botanical-style aquarium movement need to log and share information about our systems, so we can develop a model for baseline performance characteristics and expectations about these systems, and perhaps sort of develop "standards" for techniques, practices, and expectations about these tanks.

With so many people worldwide starting to play seriously with blackwater, botanical-style tanks, we're seeing more and more common trends, issues, and ways to manage them...a necessary evolution, and one which we can all contribute to!


So, your testing regimen should include things like pH, TDS, alkalinity, and if you're so inclined, nitrate and phosphate. Logging this information over time will give us all some good data upon which to develop our expectations and best practices for water quality management. And a "hot tip"- spend the extra money and get digital testing equipment when you can.

Yeah, I know that they're more expensive than test kits using liquid reagents- but with our tinted water, you won't find yourself struggling to interpret results. Oh, and they're usually quite a bit more accurate than liquid reagent test kits, too. No chemicals to degrade or run out of- just batteries, and you need to calibrate them periodically.

They're a  good long term investment for your hobby! 

Last, but absolutely not least- one of the most important parts of your "life with botanicals" is observing and enjoying your tank!

Understanding what's going on- expecting the biofilms, decomposition, etc. is only part of the process- that "mental shift" we talk about so much. The rest is observation of your animals and their reactions, behaviors, and overall health. How are they eating, coloring up, behaving? Have you noticed any changes- positive OR negative- since starting your blackwater adventure? Are they spawning? Have they stopped spawning? Have they started dying?

I mean, shit-it's that basic.

And THAT important.

In the end, living with your botanical-style backwater aquarium isn't just about a new aesthetic approach.This is where the "mainstream aquarium media" (LOL) gets it all wrong and really "short-sells" this stuff... It's about understanding and processing what's happening in the little aquatic ecosystem you've created. It's about asking questions, modifying technique, and, yeah, playing hunches- all skills that we as hobbyists have practiced for generations. When you distill it all- we're still just "keeping an aquarium"-but one that I feel is a far more natural, dynamic, and potentially game-changing style for the hobby.

One that we need no longer be afraid of.


And part of losing that fear is developing consistency, and understanding what to expect over the long term, as outlined above. And yes- one of the most important behavioral characteristics I think we can have in this hobby, besides patience, is consistency.

Like, doing the same thing on a regular, continuous basis. Duh. It's not exactly a revolutionary concept in the aquarium world, but it's a very "foundational" practice/principle, isn't it? I mean, if you're trying to create and maintain a consistent set of environmental conditions, it's pretty damn important!

Now, we receive a lot of emails from hobbyists who ask us how to keep their blackwater tanks consistent (in regards to the "visual tint"), but likely the environmental parameters, as well. Sure, this may seem almost ridiculously intuitive to most hobbyists, but it's such a common concern with hobbyists, that I can't help but consider that we might be overthinking it just a bit.

I mean, environmental consistency is not too difficult to achieve, even in an aquarium with lots of botanical materials. You just have to remember a few things.

As we have discussed for years here (in fact- RIGHT HERE in this blog, lol), botanicals are "ephemeral" in nature, and tend to break down and decompose over time after submersion. In order to maintain "consistency" and stability of the environment, we need to replenish/replace them.

The act of replacing the decomposing leaves and botanicals not only mimics the processes which happen in nature (new materials being deposited into the waters), but it serves to continuously "refresh" or perpetuate the conditions within the aquarium. A sort of "mandatory husbandry process" that just happens to be the best way to maintain ANY type of aquarium for the long term, IMHO!

Fortunately, these materials are now more easily available to hobbyists than in years past! (In fact, we know a place...)

Interestingly, in Nature, many leaf litter bed accumulations in Amazonian streams, for example, have been monitored for long periods of time (years), and they have become regular "features" of the stream in which they reside, influencing not only the physical structure of the stream, but the flow rates, dissolved oxygen levels and other chemical parameters; and of course, the fish population (in both composition and numbers) as well.

Much like in nature, the way you maintain your botanicals in your system can influence these things as well. This is why I feel that the botanical-style blackwater aquarium is very similar to a reef aquarium, or a heavily-planted aquarium. There is a continuous and dynamic "evolution" that occurs throughout the existence of these aquariums, and the direction it goes is absolutely influenced by the degree to which we as hobbyists are involved. A more 'holistic" approach is warranted.

So, to summarize this now monstrous blog, here is my "top 7 list"of long-term maintenance considerations for botanical-style aquariums:

1) Start slowly, gradually building up your quantities of botanical materials over a period of weeks or months, until you reach a level that you like aesthetically, and which provides the type of manageable environmental parameters you are comfortable with.

2) Employ basic, common-sense husbandry protocols, like weekly small water changes, careful feeding, use and replacement of chemical filtration media.

3) Stock your aquarium with fishes gradually, over a period of months, preferably with smaller fishes that can "grow with the aquarium" and produce less metabolic waste during the critical first few months as your system establishes itself.

4) Regularly monitor basic water parameters over the first couple of months to establish a "baseline" of how your aquarium functions and runs chemically. Continue this practice throughout the lifetime of the aquarium.

5) Regularly remove and/or replace decomposing botanicals (or NOT- depending upon your preference) with new ones, to help keep the same visual "tint" and consistent TDS/pH parameters.

6) Note any trends or deviations from the "baseline" over time and adjust as needed to stay within a fairly tight range.

7) Stay calm, move slowly, and make adjustments with finesse.

Well, that sums it up for now, I should think!

Stay diligent. Stay thoughtful. Stay engaged. Stay methodical. Stay consistent...

And Stay Wet.


Scott Fellman

Tannin Aquatics

Scott Fellman
Scott Fellman


Leave a comment