To stay or not to stay?

One of the most commonly discussed and hotly debated topics among those of us into botanical-style aquarium lovers is the decision to remove leaves and botanicals from our aquariums as they break down, or to leave them in place.

It’s a pretty fundamental aspect of our aquarium practice, yet it sort of flies in the face of “conventional” aquarium keeping practices for many years. We have collectively embraced and almost “clinical sterility” in our aquariums, eschewing anything which seems to fly in the face of our aesthetic sensibilities and 

The definition of “decompositon” is pretty concise:

de·com·po·si·tion- dēˌkämpəˈziSH(ə)n -the process by which organic substances are broken down into simpler organic matter.

We add leaves and botanicals to our aquariums, and over time, they start to soften, break up, and ultimately, decompose. This is a fundamental part of what makes our botanical-style aquariums work. Decomposition of leaves and botanicals not only imparts the substances contained within them (lignin, organic acids, and tannins, just to name a few) to the water- it serves to nourish bacteria, fungi, and other microorganisms and crustaceans, facilitating basic "food web" within the botanical-style aquarium- if we allow it to!

In an aquarium set up to take advantage of these materials and their function, the leaves and botanicals begin to soften and ultimately break down, they will foster microbial growth, biofilms, and fungal growths- all of which will provide supplemental foods for the resident fishes...just like what happens in Nature. 

Again, this is a step that we need to take- an understanding that we need to have- that botanical-style aquariums are more than just some style of aquascaping. They are closed aquatic ecosystems, set up to optimize natural processes, while providing a wide variety of benefits for their inhabitants.


Facilitating these processes- allowing the materials to accumulate naturally and break down "in situ" is a key component of replicating and supporting these functional microhabitats in our aquariums. The typical aquarium hardscape- artistic and beautiful as it might be, generally replicates the most superficial aesthetic aspects of such habitats, and tends to overlook their function- and the reasons why such habitats form in the first place in Nature.


Of course, accepting this process in our aquariums means that we need to embrace an entire compliment of organisms and their “work” within our aquariums.

Decomposers, which include bacteria, fungi, and other microorganisms, are the other major group in the food web. They feed on the remains of other aquatic organisms and plants, and in doing so, break down or decay organic matter, returning it to an inorganic state. 


Some of the decayed material is subsequently recycled as nutrients, like phosphorus (in the form of phosphate, PO4-3) and nitrogen (in the form of ammonium, NH4+) which are readily available for plant growth. Carbon is released largely as carbon dioxide that acts to lower the pH of the aquarium water.

We need to get over the "block" which has espoused a sanitized version of Nature. I hit on this theme again and again and again, because I feel like globally, our community is like 75% "there"- almost entirely "bought in" to the idea of really naturally-appearing and functioning aquarium systems.

Understanding that stuff like the aforementioned decomposition of materials, and the appearance of biofilms- comprise both a natural and functional part of the microcosms we create in our tanks.

This is true in both the wild habitats and the aquarium, of course.

The same processes and function which govern what happens to these materials in the wild occur in our aquariums. And, if we reject our initial instinct to "edit" what Nature does, the aquarium takes on a look and vibrancy that only She can create.

Embrace, don't edit.

Leave the stuff in there until it decomposes.

Stay open-minded. Stay thoughtful. Stay creative. Stay observant...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



Scott Fellman
Scott Fellman


3 Responses

Joshua E Morgan
Joshua E Morgan

September 25, 2020

Good1 Thank you :)

Scott Fellman
Scott Fellman

September 24, 2020

Hi Joshua,

Your procedure is exactly what I would do if that were my concern. When I change water, i will typically give the upper layers of the leaf litter a little “shake” and if stuff happens to rise up into the water column, I grab it with the siphon hose..You’re right on it!


Joshua E Morgan
Joshua E Morgan

September 24, 2020

Here’s a question for you…how do you remove fish detritus from a botanical-rich system? When I had my licorice gouramies, I wasn’t really on top of the whole gravel vacuuming concept…I did not realize how important it is to remove fish waste for the health of the animals. Of course, in a botanical rich tank, we don’t want to remove much of the leaf detritus…would I just clean the top of the substrate the ‘normal’ way (in my case, I gently blast the top of the substrate with a turkey baster while using my gravel vacuum above it) and accept that some of the botanical detritus will unintentionally be lost? And would it be beneficial to have some kind of substrate under the leaf litter and other botanicals?

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