All in all, it's best NOT to kill your fishes...

That's quite probably my most literal title ever.  And it's something I sincerely believe in!

Killing your fishes really sucks. Particularly when it's avoidable.

And, now that I have your attention, let me explain a bit more.

Yeah, our little sector of the aquarium hobby is exploding...And with an explosion of interest comes a flurry of new people, new ideas, and some of the same old questions. And worse, occasionally, the same old bad habits!

Uh- oh!

Like many of you, I've made my share of errors in this hobby.

When I started playing with botanicals in my aquariums almost two decades ago, I made a fair number of mistakes. Sometimes, they cost the lives of my fishes. And killing fishes sucks.


Some mistakes were caused by my lack of familiarity with using various materials. Others were caused by not understanding fully the impact of adding botanical materials to a closed aquatic ecosystem. All were mitigated by taking the time to learn from them and honestly asses the good, the bad, and the practical aspects of using them in our aquariums. 

And sometimes, that meant developing "best practices" to help mitigate or eliminate issues as much as possible, even though the "practices" may not be the easiest, most convenient, or expedient way to proceed.

After more than four years of running Tannin, I have pretty much identified the two most common concerns for customers associated with utilizing botanicals in their aquariums. Curiously, our two biggest concerns revolve around our own human impatience and mindset- not the botanical materials themselves.

The first is... preparation.

We are often asked why we don't feel that you can, without exception, just give any of your botanicals "a quick rinse" and toss them into your aquarium.

After all, this is what happens in nature, right? Well, shit- yes...but remember, in most cases, there is a significant "dilution factor" caused by larger water volumes, currents, biologically-rich substrates, etc. that you encounter in natural aquatic systems. Even in smaller bodies of water, you have very "mature" nutrient export systems and biological equilibriums established over long periods of time which handle the influx and export of organic materials.  

However, even in Nature, things go awry, and you will occasionally see bodies of water "fouled" by large, sudden influxes of materials (often leaves, grass clippings, etc.)- sometimes after rain or other weather events- and the result is usually polluted water, large algal blooms, and a pretty nasty smell! 

In the aquarium,  of course, you have a closed system with a typically much smaller water volume, limited import of fresh water, limited filtration (export) capacity, and in many cases, a less robust ecological microcosm to handle a large influx of nutrients quickly.

So you know where I'm going with this:

Fresh botanical materials, even relatively "clean" ones, are often still "dirty", from collection, storage, etc. They may have dust, airborne pollutants, soil or silt (depending upon where they were collected), even cobwebs, bird droppings, and dead insects (yuck!).

Natural materials accumulate "stuff." They're not sterile; made in some clean room in a factory in Switzerland, right? 

So," just giving botanicals a quick rinse" before tossing them in your tank is simply not good procedure, IMHO- even for stuff you collect from your own backyard. At the very least, a prolonged (30 to 60 minute) steep in boiling hot water will serve to "sterilize" them to a certain extent. Follow it with a rinse to remove any lingering dirt or other materials trapped in the surfaces of your botanicals.

Now, I don't recommend this process because I want to be a pain in the ass. I recommend it because it's a responsible practice that, although seemingly "overkill" in some people's minds- increases the odds for a better outcome.

The guys up in the cockpit on your flight from L.A. to New York know every system of the Boeing 737 that they fly. But guess what? They still complete the pre-flight checklist each and every time they hop in the plane.

Because it can save lives.

Why should we be any different about taking the time to prepare botanicals? I know it sounds harsh; however, if you skip this step and kill your fishes- it's on you.


What would you skip this, other than simply being impatient?

Could you get away with NOT doing this? 

Sure. Absolutely. Many people likely do. 

But for how long? When will it catch up with you? Maybe never...I know I'll get at least one email or comment from a hobbyist who absolutely doesn't do any of this and has a beautiful healthy tank with no problems.

Okay, good for you. I'm still going to recommend that you embrace a preparation process.

Boiling/steeping also serves a secondary, yet equally important purpose: It helps soften and even break down the external tissues of the botanical, allowing it to leach out any remaining subsurface pollutants, sugars, or other undesirable organics to the greatest extent possible. And finally, it allows them to better absorb water, which makes them sink more easily when you place them in your aquarium. 

Yes, it's an extra step.

Yes, it takes time.

However, like all good things in nature and aquariums, taking the time to go the extra mile is never a bad thing. And really, I'm trying to see what possible "benefit" you'd derive by skipping this preparation process?

Oh, let me help you: NONE.


There is simply no advantage to rushing stuff.

Like all things we do in our aquariums, the preparation of materials that we add to them is a process, and Nature sets the pace. The fact that we may recommend 30 minutes or more of boiling is not of concern to Nature. It may take an hour or more to fully saturate your Sterculia Pods before they sink.

So be it.


Savor the process. Enjoy every aspect of the experience.  And don't you love the earthy scent that botanicals exude when you're preparing them.

Now, I will quickly address (for the "umpteenth time", as they say) that most commonly-asked question, which primarily pertains to leaves: "All of this boiling  and soaking- doesn't it release all of those tannins that you're wanting to embrace and have in your aquarium?"

Well, to put it very simply, the answer is, "No." 

Yes, direct, I know...but it's true! 

At the risk of over-simplifying things, remember that leaves and plant materials have structures which break down over time, and release whatever materials (residual sugars, other organics, and of course, tannins) remain bound up in them. The boiling may, indeed break down some outer layers, allowing some of these materials to release, and water to saturate tissues, but unless you're boiling these materials for hours and hours, there will be plenty of those tint-producing tannins still yet to be released.

So, at the very least, a good rinse and perhaps an overnight soak in water will serve to soften up the leaves, leach out some surface pollutants, and provide some confidence that you're being proactive.

So in summary- we recommend some form of preparation for every botanical item you add to your aquariums.

Trust me- it's another instance where the perceived "trade-off" isn't even close.

You'll have plenty of those nice, tint-producing  tannins to work with, and the security of knowing that you've taken some steps to keep pollution to a minimum during the process.

And of course, there is still one more question which arises out of the prep process:

"Can I use the "tea" that results when you boil or soak leaves and botanicals?"

My answer? You could, but I won't. Ever.

Why? Let me explain:

Many hobbyists want to make use of the water in which the initial preparation of our botanicals takes place in as a form of "blackwater tea" or "blackwater extract."

Now, while on the surface, there is nothing inherently "wrong" with the idea, I think that in our case, we need to consider exactly why we boil/soak our botanicals before using them in the aquarium to begin with. 

What do I do?

I discard the "tea" that results from the initial preparation of botanicals- and I recommend that you do, too. 

Here's why:

As I have mentioned many times before, the purpose of the initial "boil and soak" is to release some of the pollutants (dust, dirt, etc.) bound up in the outer tissues of the botanicals. It's also to "soften" the leaves/botanicals that you're using to help them absorb water and sink more easily. As a result, a lot of organic materials, in addition tannins and humic substances are released.

So, why the #$%@ would you want a concentrated "tea" consisting of of dirt, surface pollutants, and other organics in your aquarium as a DIY "blackwater extract?" And how much do you need? Like, what is the "concentration" of desirable materials in the "tea" relative to the water? How do you know HOW MUCH to add to your aquarium?

I mean, it's not an easy, quick, clean thing to figure, right?

There is so much we don't know. 

A lot of hobbyists tell me they are concerned about "wasting" the concentrated tannins from the prep water. Trust me, the leaves and botanicals will continue to release the tannins and humic substances (with much less pollutants!) throughout their "useful lifetimes" when submerged, so you need not worry about discarding the initial water that they were prepared in.

To me, it's a no-brainer: It's kind analogous to adding the "skimmate" (the nasty concentrated organics removed by your protein skimmer via foam fractionation in your marine aquarium) back into your aquarium because you don't want to "lose the tiny amount of valuable salt or some trace elements" that are removed via this process.

Would you add this concentrated shit into your reef tank?

Is it worth polluting your aquarium for this?

I certainly don't think so! 

Are botanicals THAT "dirty" to begin with? Likely not.  Is this being a bit conservative? You might say that. I think it's just being responsible. 

Do a lot of hobbyists add the "tea" and get away with this? Sure. In Nature, don't leaves, wood, and seed pods just fall into the water? Of course.

However, in most cases, Nature has the benefit of dissolution from thousands of gallons/litres of water, right? It's an open system, for the most part, with nutrient import and export processes far superior to and more efficient than anything we can hope to do in the confines of our aquariums! 

Okay, I think I beat that horse up pretty good!

I mean, could you experiment with this stuff? Sure. At your own risk. As a business, and as a hobbyists who wants to see the idea of botanical/blackwater aquariums grow in the hobby, it's my responsibility to recommend the most conservative practices that we hope will create good outcomes for the widest variety of people.

If you want to use the water from the "secondary soak", I'd feel a lot better about that..The bulk of the surface pollutants will have been released at that point. However, I still just don't like the idea. Better yet is the process of adding some (prepared) leaves/botanicals to the containers holding the makeup water that you use in your water exchanges. The materials will steep over time, adding tannins and humic substances to the water.

How much to use?

Well, that's the million dollar question.

Who knows? Even that is a guess and decidedly unscientific at best! 

It all gets back to the (IMHO) absurd "recommendations" that have been proffered by vendors over the years recommending using "x" number of leaves, for example, per gallon/liter of water. There are simply far, far too many variables- ranging from starting water chem to pH to alkalinity, and dozens of others- which can affect the "equation" and make specific numbers unreliable at best. 

Now, nothing is perfect.

Nothing we can tell you is an absolute guarantee of perfect results...You're dealing with natural materials, and the results you'll see are governed by natural processes that we can only impact to a certain extent by preparation before use. But it's a logical, responsible process that you need to embrace for long-term success.

And when it comes time to adding your botanicals to your aquarium, the second "tier" of this process is to add them to your aquarium slowly. Like, don't add everything all at once, particularly to an established, stable aquarium. Think of botanicals as "bioload", which requires your bacterial/fungal/microcrusacean population to handle them.

Bacteria, in particular, are your first line of defense.

If you add a large quantity of any organic materials to an established system, you will simply overwhelm the existing beneficial bacterial population in the aquarium, which will likely result in a massive increase in ammonia, nitrite, and organic pollutants. At the very least, it will leave oxygen levels depleted, and fishes gasping at the surface as the bacteria population struggles to catch up to the large influx of materials.

This is not some sort of esoteric concept, right? I mean, we don't add 25 3-inch fishes at once to an established, stable 10-gallon aquarium and not expect some sort of negative consequence, right? So why would adding bunch of leaves, botanicals, wood, or other materials containing organics be any different?

It wouldn't.

So please, PLEASE add botanicals to your established aquarium gradually, while observing your fishes' reactions and testing the water parameters regularly during and after the process. Take measured steps.

There is no rush.

There shouldn't be.

It's interesting how the process of selecting, preparing and adding botanical materials to our aquariums has evolved over the time since we've been in business. Initially, it was all about trying to discover what materials weren't "toxic" in some way! Then, it was about figuring out ways to prepare them and make sure that they don't pollute the aquarium. Finally, it's been about taking the time to add them in a responsible, measured matter.

I think our biggest "struggle" in working with botanicals is a mental one that we have imposed upon ourselves over generations of aquarium keeping:  The need to control our own natural desire to get stuff moving quickly; to hit that "done"

And the reality, as we've talked about hundreds of times here and elsewhere, is that there really is no "finished", and that the botanical-style aquarium is about evolution. This type of system embraces continuous change and requires us to understand the ephemeral nature of botanicals when immersed in water.

I know I may be a bit "blunt" when it comes to these topics of preparation, practices, and patience- but they are critical concepts for us to wrap our heads around and really embrace in order to be successful with this stuff.

All caveats and warnings aside, the art and evolving "science" of utilizing natural botanical materials for the purpose of enriching and influencing the environment of the aquarium is an exciting one, promising benefits and breakthroughs that we may not have even thought about yet! It's okay to experiment. However, if you ask me- and a lot of you do- about what I recommend- I'll give you an honest- albeit long-ass- answer! 

Botanicals provide a unique, natural aesthetic which we have embraced and utilized to create inspiring aquatic displays to share with aquarists and non-aquarists alike. With some many potential applications for botanical materials in aquariums, the future is bright and wide open for discoveries and even breakthroughs!

We just need to apply some of the same common-sense hobby "basics" which got us to this point..and maybe to pick up a few new skills along the way as well!

Stay excited. Stay measured. Stay patient. Stay disciplined. Stay curious...

And Stay Wet.


Scott Fellman

Tannin Aquatics  

Scott Fellman
Scott Fellman


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