How not to kill your fishes with botanicals...

Okay, now that I have your attention...

Like many of you, I've made my share of errors in this hobby. In particular, when I started playing with botanicals in my aquariums almost two decades ago, I made a fair number of mistakes. And of course, when I started Tannin, and sourced and utilized botanicals, I mades a lot of mistakes, too! 

Some where 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. 

After 3 years of running Tannin, we have pretty much identified the two most common concerns I have that are associated with utilizing botanicals. Curiously, our two biggest concerns both revolve around our own human impatience and mindset...


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, 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, 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."

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 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.

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, 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.

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 of boiling is not of concern to Nature. It may take an hour or more to fully saturate your "Savu Pods" and sink them. So be it.


Savor the process. Enjoy every aspect of the experience. 

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 bark 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, there will be plenty of those tint-producing tannins still yet to be released.

So, at the very least, a good rinse and perhaps a brief soak in warm water will serve to soften up the leaves, leach out some surface pollutants, and provide some confidence that you're being proactive. We have made it a point to create an "evolving document", if you will, covering the preparation of each and every botanical that we offer. It's not perfect, and we try to update it as often as possible to keep it up-to-date with our latest thinking on this matter. However, I think it's a great reference for this process.

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.

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 population to handle them.

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 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 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 aquarium gradually, while observing your fishes' reactions and testing the water parameters regularly during and after the process. 

There is no rush.

There shouldn't be.

It's interesting how the process of preparing and adding 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:  The need to control our own natural desire to get stuff moving quickly; to hit that "done" thing fast. And the reality, as we've talked about hundreds of times here and elsewhere, is that there really is no "finished" (as we discussed yesterday), and that the botanical-style aquarium is an evolution, which embraces continuous change and requires us to understand the ephemeral nature of botanicals when immersed in water.

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. Oh, and they provide a unique, natural aesthetic which we have embraced and utilized to create inspiring aquatic displays to share with aquarists and non-aquarists alike.

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

And Stay Wet.


Scott Fellman

Tannin Aquatics  

Scott Fellman
Scott Fellman


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