The water turns brown...

One of the things I've greatly enjoyed over the years (and one that has made me a consistent pain in the ass for the hobby in general), is my love of questioning stuff that we seem to take as "hobby gospel" for generations. For example, the idea that an aquarium needs to be an immaculate, sparkling clear system without any materials or organics accumulating on the bottom or elsewhere in the system.

Even now, some three years since the launch of Tannin Aquatics- well into a more "everyday" approach to creating and maintaining blackwater, botanical-style aquariums, we still occasionally hear the admonition that we're doing things in a "reckless, dangerous manner" that can create disastrous consequences for our fishes. The implication is that somehow we're going sort of "contrary" to the way people have kept aquariums successfully for generations, and that this is simply reckless.

Well, yeah. It's contrary. Of course.

But "reckless?" I think not.

And guess what? A mismanaged "classic" freshwater community tank can spell disaster for its inhabitants if you don't maintain it properly. 

You can't ignore the way nature functions and expect a success in a glass box.

News flash.

And yes, aquariums with high quantities of organic materials breaking down in the water column add to the biological load of the tank, requiring diligent management. This is not shocking news. Frankly, I find it rather amusing when someone tells me that what we do as a community is "reckless", and that our tanks look "dirty." As if we don't see that or understand why...

Now, when you think about it, the botanical-style aquarium sort of falls into that category, huh? Leaves and botanicals certainly add to the organic load, and are most definitely materials which accumulate within the tank, right? And they look very different than what we are used to seeing.

The water turns brown.

We've rehashed that like 4,000,000 times here.

Is this a negative? 

If you look at a lot of the underwater photos and videos taken in the natural habitats of our fishes that, thankfully, are becoming more and more popular and abundant than ever, you see a lot of "stuff" in the water column, on the bottom, etc.  And the water is not always crystal-clear blue white, right? It's...well, brown. Natural streams are not always the pristine-looking "nature aquarium" subjects of our dreams, are they?

No, not really.

Rather, many of the environments from which the fishes we love hail are anything but "pristine" assemblages of rock, wood, and plants. They have a lot of "stuff" in them, ranging from clumps of algae to seed pods, palm fronds, etc, up to submerged logs.

Now, in many of the photos and videos that I've poured over in recent years, the most common items you see on the bottom are...wait for it- leaves! Yeah, they're almost every aquatic environment you see, ranging from ponds to slow moving jungle streams, to larger rivers. Sure, in some swift-current scenarios, you're less likely to see large beds of leaves, but you still see them. 

Which is why, when I first started playing with leaves, that I was so astounded that more hobbyists haven't incorporated them into their displays.

Oh, sure, you'd see them in the tanks of a few biotope freaks, which were seen largely as "fringe-dwelling" novelties- and maybe in some setups of dedicated cichlid and betta breeders- but that was really the extent of it. Once I got over my "reefkeeping" mindset of not adding all sorts of stuff to a tank, I was able to look at it objectively. 

As we've discussed ad naseum here, I think one of the biggest initial reason was that the look was utterly "alien" to our aquarium aesthetic sensibilities. I mean, "Clutter" on the bottom? Brown water?

How is that "natural?"

And, perhaps even more important, the idea of throwing things like leaves and seed pods into a tank- a carefully managed artificial world, seemed like simply "polluting" what was long suggested should be as pristine a system as possible. And that brown water= "dirty", right?

Yeah. A lot of aquarists still equate tannin-stained water with "dirt."

I hear this a lot when I speak at clubs, showing hobbyists the wonders of the blackwater aquarium world. It's still kind of hard for many to get their heads around, despite us showing videos and pics up the ass of all sorts of blackwater habitats.

I know, I know- an aquarium is not an open, natural system, yet if well-managed, it can function beautifully for years and years, right?

So there are really two huge factors that have been touted as the reason for not doing what we are doing over the years: One is based on the prevailing mindset of what the hobby thinks a tank should look like, and the is other based on a perception that there is a negative the environmental impact on a "carefully constructed aquarium environment." Both are valid points, I suppose- although the comical part to me is the automatic assumption that we're not working with "carefully constructed aquatic environments" here.

Why? Because the water is...brown?

After years of experimenting with leaves, botanicals, and other natural materials in aquariums, and with a growing global community of hobbyists doing the same daily, the mental roadblocks to this approach are starting to fall. We're seeing all sorts of tanks being created by all sorts of hobbyists, which in years past would garner far more hushed whispers and criticisms than gasps of envy.

It's taken a while, but the pockets of resistance are fewer and farther in between than in years past, at least from where I sit!

So, it's still necessary to address this stuff from time to time, as there are still many unanswered questions from those not familiar with our game here.

And, with the above historic concerns in mind, what exactly is the impact of a bunch of stuff on the bottom in your tank?

Well, on the most superficial of levels, the water turns brown. We know that.

And, if your water has a lower general hardness, it shifts towards an acidic pH. Again, something we already know. So what are the other impacts? Well, for one thing, decomposing material of plant origin probably contains stuff like sugars, lignin, and all sorts of organic compounds. Some of these substances are utilized by various organisms, like bacteria and fungi, which work to break it down. Algae, and plants (if present) will utilize some of them as well, such as phosphates, nitrates, etc.

Now, the "organics" that we have used as a red flag to discourage throwing this stuff into tanks in years past can accumulate and even be problematic- if you don't have necessary control and export processes in place to deal with them. What would these processes be? Well, to start with- Decent water movement and filtration, to physically remove any debris. Use of some chemical filtration media, such as organic scavenger resins, which tend not to remove the "tint", but act upon specific compounds, like nitrate, phosphate, etc.

And of course, water exchanges. Yeah, the centuries old, tried-and-true process of exchanging water is probably the single most important aspect of nutrient control and export for any system, traditional, botanical, etc. There is no substitute for diluting organic impurities through regularly-scheduled water changes, IMHO.

This isn't some revelation.

And those are only some of the most obvious aspects of nutrient control and export, really. It even gets down to stuff like not overstocking and overfeeding your tank. Carefully removing uneaten food.

Nothing that is really out of the ordinary, right?

I can tell you from experience in every botanical-style tank that I have set up since 2012, that I have never experienced more than barely detectible levels of nitrate (like, less than 5ppm, if at all) and phosphate (like 0.05ppm or less). This despite large amounts of leaves, seed pods, etc. being present. I don't have some "magic touch."

Sound, time-tested husbandry techniques will make managing a heavily-botanical-laden aquarium as easily manageable as any other aquarium system, in my experience.

Certainly as forgiving as any Mbuna tank, "high tech planted tank", or  "SPS" reef system that I've played with over the years! We just utilize a slightly different "operating system" to do what hobbyists have done forever.

When people see things like biofilms, fungi, and possibly even a little algae forming on botanicals and wood in an aquarium for the first time, the initial reaction for many would be to freak out and immediately submit to the "I told you so's" offered up by the "armchair experts" who've never ran a botanical-style tank, yet feel compelled to offer "advice" on how to "rehab" it. As a newcomer to this tinted world, you might be rattled enough to "take corrective action!"

Before running off and tearing your tank apart- examine it.

Look at the water chemistry. Look at the fishes.

Take another look at some underwater pics and videos of natural habitats and realize that this is exactly what to expect in a system where these materials are present. And take comfort in knowing that, in an aquarium, these biofilms are part of the normal natural function of systems with materials like leaves and botanicals, and the heaviest concentrations will typically subside once the aquarium establishes itself (great news if you just can' get over that). A "mental shift", patience, and the passage of time are the main "corrective measures" you need to employ here.

Oh, and a desire to understand what's happening...


Now again, I'm speaking from my personal experience with many tanks set up in this fashion. I'm not a scientist, having completed a huge number of water quality experiments of every conceivable type on my tanks. And I'll tell you categorically that if you approach the management of a botanical-style blackwater aquarium in a nonchalant, irresponsible manner, you'll be in for a humbling experience.

I'll say it yet again: In my experience, there is nothing inherently more challenging or more dangerous about these types of tanks than there is with any other speciality system. The fact that the water is brown doesn't mean that a well-managed tank is any closer to disaster than any well-managed clear water system.

I think that I do a pretty good job of managing the water quality in my aquariums. There's no magic here. Like many of you, I do the work necessary to keep my aquariums operating in a healthy state. In my opinion, NO aquarium of ANY type is "set and forget", and you'll be in for a rude awakening with a blackwater, botanical-style tank- or any tank- if you take that approach.


And, with the scientifically-validated benefits to fish from humic substances present in blackwater, the "upside" to what was long popularly perceived as dirty tanks is becoming more and more obvious. And the aesthetics, dynamics, and interest created in your aquarium by "that brown water" can become a fascinating, obsessive new passion for you within the aquarium hobby if you're not careful!


For those of us who "feel it", this is a real enlightenment...a compulsion. An obsession!

So, to those of you who face the occasional "tease" from your clear-water-loving brethren, keep applying skill and common sense to your aquariums. Delight in the difference.

Yeah, the water turns brown.

We get that.

Stay focused on husbandry. Stay engaged with the community. Lead by example. Experiment. Educate. Enlighten.

Share what you've learned. 

Stay excited. Stay fascinated.Stay on top of this stuff...

And Stay Wet.


Scott Fellman

Tannin Aquatics


Scott Fellman
Scott Fellman


5 Responses

Scott Fellman
Scott Fellman

July 12, 2021

Hi Enya,

You’ve madrone of the most profound observations/statementsaboutthis. “…as longs the fishes are happy…” That means EVERYTHING, IMHO. Trust me, your fishes- your tank-will let you know when things aren’t right. And the"look" isn’t always indicative of water quality- good or bad. And the reality is that, over time, if the wood is causing the color due to tannin leaching, it will subside over time, with water exchanges, etc.



July 08, 2021

My sister has bee making fun of me for months telling me my tank is dirty and I need to clear the brown water from my tank. The drift wood in my tank is still pretty new and is also a very dark colored wood (I did not boil the wood prior to adding it to the tank). As a result it releases a lot of tannins in my water making it very dark brown at times, but all the levels in my tank say the quality is perfectly fine and all my fish look to be doing great! Am I a bit disappointed that sometimes its difficult to see some of my small, orange, or reddish colored fish? certainly, but as long as they are happy, I’m happy. I made my tank to be as natural as possible, and it was a struggle against the brown water for a while, but, I’ve accepted that its a naturally occurring color resulting from my attempt to make a natural ecosystem type tank. I now love my tank knowing I’ve succeeded in the natural build I desired even though the water is quite brown.

Scott Fellman
Scott Fellman

July 31, 2020

Hey Sarah,

Thanks for stopping by!

Yeah- it IS a sort of “mental shift” we have to make when “going dark.” It’s contrary to so much of what we]ve been taught is “normal” in the hobby- crystal clear blue-white water, spotless sand, etc. Once you explore the natural habitats of our fishes (virtually or in person), you realize that the way we interpret Nature in the hobby, and the way it actually IS are often quite different from each other. Regardless, it’s not something everyone likes…But once it gets into your head…well!



July 30, 2020

This is so cool! I just started my first shrimp tank. Started by cycling a tiny 1.5 gallon tank with plants and spiderwood for 3 months and just added the shrimp last weekend. My water started clear, but it now has a yellow tinge bc of the spiderwood and leaves i added. My boyfriend thinks it’s unsightly, but I insisted that this is natural and that the shrimp love it. i’m new to the hobby, so i’m glad that there are other people who don’t mind a little tint to their tanks. i prefer it!


February 16, 2020

Hi Scott

Your article is the first of heard about. I always wondered if a lake or pond etc environment could be exactly duplicated. I guess it can. I’m assuming it involves more water changes and monitoring than a clear water tank. I admire your tenacity in figuring and making it work. I would be interested in knowing what extra maintenance if any is required. Thanks

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