The long haul: Thoughts on the long-term maintenance of botanical-style/blackwater aquariums

We've started to think a lot about the long-term maintenance of blackwater, botanical-style aquariums. One of the interesting things is that the general hobby's perception about blackwater aquariums was, for a very long time, that these systems were just sort of "stunts", and had no real "long-term outlook", as they could not be maintained for indefinite periods.

At first, I thought this was just the assertions of a few random people on forums here and there, but upon further investigation in the years before I launched Tannin, it seemed that nearly everywhere I looked I found a similar pessimism about the long-term viability of these types of aquariums. 

Perhaps part of it could be explained away by the fact that blackwater conditions have, over the years, been recommended for "conditioning" fishes, or for breeding aquariums for certain types of fishes, not really for the long-term maintenance of fishes. So they might never have been viewed as the types of aquariums you keep going long-term.

Interestingly, one segment of the aquarium hobby- shrimp keepers- has a good body of experience with the long-term maintenance of lower ph/alkalinity systems, and many of these hobbyists have enjoyed significant long-term success by employing some consistent, although perhaps slightly specialized husbandry practices.

And, as we've talked about before, 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..."

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 3.5 years, and the only reason I broke down the 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.

Since the typical botanical-style blackwater aquarium is set up with an initial "inventory" of leaves and other botanicals, we are accustomed to gradually "building up" the amount of these materials in our systems over a span of time. Patience! And, because of the very nature of botanical materials (they decompose underwater...), it is necessary to regularly replace them, much as you would filter pads, activated carbon or other chemical filtration media.

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 structure of the river, but flow rates, dissolved oxygen levels and other chemical parameters, and of course, the fish population (in both composition and numbers).

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.

I think that the keys to really long-term success and stability of your blackwater/botanical-style aquarium are as follows:

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.

And of course, observe your aquarium regularly (a given), and share any insights, issues, and trends that you've noticed with the community. With so many hobbyists now getting into this interesting segment, we're starting to see some useful data on the establishment, maintenance, and long-term care of blackwater/botanical-style aquariums.

What trends and "behaviors" have you noticed in your longer-term established blackwater/botanical-style aquariums? Have you found these systems any more challenging than other aquariums you kept, or was it simply a matter of learning about how they behaved and maintaining them in such a way as to provide consistent environmental conditions?

Stay observant. Stay consistent. Stay open-minded.

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Scott Fellman
Scott Fellman


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