How to style yourself on Botanicals


There has been a definite buzz in the aquarium world recently, about what has come to be known as the ‘botanical-style aquarium’, and the chances are that you may have seen pictures of these fascinating systems, rich in life and compelling in appearance.

But what is a botanical-style aquarium? At its most simple level, it’s a system that utilizes materials from terrestrial plants to facilitate natural processes in the aquarium. 

Leaves and seed pods contain many compounds, ranging from lignin to cellulose to tannins and humic substances — all of which have an impact on the aquatic environment, both structurally and chemically.

A botanical-style tank isn’t a style of aquascaping, at least not in the sense that one would classify an Iwagumi or a diorama. 

Sure, botanicals create a different look in your aquarium, but their biggest selling point is that they facilitate a different set of functions in the aquarium. It’s more of a methodology than an aesthetic.

Using botanicals compels us to embrace certain natural elements that might make us uncomfortable, such as the formation of biofilms, fungi, the process of decomposition, and the accumulation of detritus. This requires a certain mental shift. 

Taking the plunge

We have two choices. We can resist Nature’s advances, and attempt to circumvent or thwart Her processes of decomposition, growth, and evolution. We can scrape away unsightly biofilms, we can remove detritus and algae. We can trim our plants to look neat and orderly. 

Or, we can allow Her seemingly random, relentless march. We can make a conscious decision to embrace the biofilms, fungal growth, decomposing leaves, and tinted water. We start this by accepting the look, and continue from there.

It should come as no surprise that botanical-style blackwater aquariums simply appear unusual. We fans celebrate aquariums modelled after Nature as it really is, in form and function; filled  with randomness, intricacy and mystery. 

That may sound dramatic, but those of us who play with this stuff have come to realize that botanical-style aquariums have contrasted operating parameters to pretty much any other type of system you’d keep. Like any aquarium, you need to understand, appreciate, and enjoy the characteristics, phases, and nuances of this type of set-up.

Pods and leaves; a bounty of botanicals. 

Beyond aesthetics

The biggest mental shift required is the understanding that botanical materials break down as they impart tannins and other substances into the water. A well-manicured botanicals layout will be reshaped by Nature as the leaves, seed pods, and other botanical materials are subject to biological degradation.

This is strange for us, yet it’s something that our fishes are completely familiar with. They’ve adapted over aeons to co-exist with and utilize these naturally occurring materials as hiding places, areas to forage, and sites to spawn, as a part of their daily existence. 

Thought about from such a standpoint, you can contemplate a more basic question about our hobby: “What is the purpose of an aquascape in the aquarium, besides just aesthetics?” 

Well, it’s to provide fishes with a comfortable environment that makes them feel at home, right? The botanical-style aquarium embraces this idea thoroughly. 

Botanicals as acidifiers

Many hobbyists ask about utilizing leaves and other botanicals to lower the pH in their aquariums.  

There seems to be a fair amount of misconception about what botanicals can and cannot do to the pH of the water in your aquarium. 

I field a lot of questions like, “How many leaves do I need to lower the pH and hardness in my Betta tank?” If only it were so simple! Alas, nature offers few ‘plug and play’ solutions.

Many botanicals do release acids that can lower the pH, but only if the water already has a low enough carbonate hardness (KH). Most botanicals won’t do much to significantly reduce the pH if you start with hard, alkaline water, as the KH will act as a buffer, preventing the acids from reducing the pH.

In general, it’s fairly safe to state that soft water is usually acidic, and hard water is usually alkaline.

Note that the colour of water — even the stain from leaves — is  no real indication of pH or hardness. This is a misconception that we need to dispense with once and for all.

If you really want to create soft, acidic water with botanicals, use RO or deionised water — your botanicals will have a lot more ‘play’ in terms of how they can affect the pH. Botanicals alone will NOT affect KH. End of discussion.

All that they bring

One of the things you’ll experience when first adding botanicals is an initial burst of tannins, which provide a visible tint to the water. If you’re not using activated carbon or some other filtration media, this tint will be considerably more pronounced. 

You might also experience some initial cloudiness. This could be dust, or lignin and other compounds released from the tissues botanicals. It may even be a bloom of bacteria and microorganisms. It usually passes quickly with minimal, if any intervention, and not everyone experiences this.

But one thing that unites owners of botanical-style aquaria is the appearance of that gooey, slimy, stringy stuff known as ‘biofilm.’

Biofilm. Even the word conjures up an image of something that you really don’t want in your tank. Something dirty, nasty, and potentially detrimental. 

To be candid, the dictionary definition is not going to win over many ‘haters’: bi·o·film  (noun) — a thin, slimy and usually resistant film of bacteria that adheres to a surface.

Commonly-encountered examples of biofilm include the plaque that forms on teeth, and the slime that forms on surfaces in water. But it’s not all doom and gloom.

Biofilm is a completely natural occurrence; bacteria and other microorganisms taking advantage of a perfect substrate upon which to grow and reproduce, just like they would in the wild. Freshly added botanicals offer a mother lode of organic material and surface area
for these biofilms to propagate, and that’s what happens — just like in Nature. Many fishes and shrimp will feed directly on these biofilms.

The surge of biofilm growth is typically a passing phase, and can take anywhere from a few days to several weeks before it subsides on its own. It will never fully ‘go away’ in a botanical-style tank, but then you don’t want it to. Its benefits are manifold and to be welcomed. 

Understand that biofilms are present in every aquarium, to some degree. Furthermore, they often go hand-in-hand with the appearance of fungi. Not the ones that we vilify for attacking our fish or their eggs, though. It’s easy to just heap them in with the ‘bad guys’ and the nasty implications they have. 

Fungi reproduce by releasing tiny spores that then germinate on new and hospitable surfaces. 

These aquatic fungi are intimately involved in the decay of wood and leafy material. 

Fungus is nothing to fear here.

And, of course, when you submerge terrestrial materials in water, growths of fungi tend to arise. Anyone who has ever soaked a new piece of aquatic wood for an aquarium can attest to this.

Fungi colonize wood because it offers them a lot of surface area to thrive and live out their life cycle. And cellulose, hemicellulose, and lignin — the major components of wood and botanical materials — are degraded by fungi, which possess enzymes that can digest these materials. 

Fungi are regarded by biologists to be the dominant organisms associated with decaying leaves in streams. Fishes and invertebrates that live amongst and feed directly upon the fungi and decomposing leaves, and botanicals contribute to the breakdown of these materials as well. Aquatic fungi can break down the leaf matrix and make the energy locked up inside it available to feeding animals in these habitats.

While not attractive looking, fungi are incredibly useful, and they play along with a surprisingly large number of aquatic life forms to create substantial food webs. Natural habitats are absolutely filled with this stuff.

Botanicals can be beautiful or ugly, pending your own views.

The long game 

Typically, botanicals will begin to soften and break down over a period of several weeks or months. As an aquarist, you have the option to leave them in as they degrade, or remove them — whatever your aesthetic sensibilities tell you to do! 

Many of us leave our botanicals in our tanks until they have completely decomposed, utilizing them as almost some sort of botanical mulch, which serves as a sort of supplemental food resource, especially for fry. 

So, what are the implications for managing this type of system?

Remember, you’re dealing with a tank filled with decomposing botanical materials. Good overall husbandry is necessary to keep your tank stable and healthy, and that includes regular water changes.

During water changes, I typically siphon out any debris that has moved where I don’t want it, but for the most part, I’m merely siphoning water from down low in the water column. 

A Neon tetra hunts naturally occurring copepods in a botanical-style aquarium.

The importance of community

Regular water testing is particularly important, and not just for the information you’ll gain about your aquarium and its trends. 

It’s important because we as proponents of the botanical-style aquarium need to log and share information about our systems, so we can develop a model for ‘baseline performance’, and perhaps look to develop standards for techniques, practices, and expectations about these tanks. 

We’re seeing more and more common trends, issues, and ways to manage them — a necessary evolution, and one which we can all contribute to. 

Any testing regimen should include pH, TDS, and alkalinity, and if you’re so inclined, nitrate and phosphate. Logging this information over time will give us good data upon which to develop our expectations and best practices for water management.

In the end, living with your botanical-style backwater aquarium isn’t just about a new aesthetic approach. It’s about understanding and processing what’s happening in the little aquatic ecosystem you’ve created. It’s about asking questions, modifying technique, and playing hunches; skills that we as hobbyists have practiced for many generations. 

When you distill it all, we’re still just keeping an aquarium — just one that I feel is a far more natural, dynamic, and potentially game-changing methodology for the hobby. One that we need not be afraid of.

Stay the course. Don’t be afraid. Open your mind. Study what is happening. Draw parallels to the natural aquatic ecosystems of the world. And know that the pile of decomposing goo that you’re looking at now is just a metaphorical ‘stepping stone’ on the journey to an aquarium which embraces Nature in every conceivable way. 

And of course, the literal basis for all of this stuff is the botanical materials themselves, breaking down in our tanks, just like they’ve done in Nature for millions of years.

I hope that, as the years go by, we as a hobby will overcome generations of fear over stuff like detritus and fungi and biofilms. Maybe, rather than attempting to ‘erase’ these things, which go against our ‘gram-influenced aesthetics’ of how we think that Nature should look, we might want to meet Nature where She is and work with Her. 

If we’re lucky, we just might see the real beauty — and benefits — of Nature in Her most compelling and unedited form.

Words by Scott Helman

Editor’s note: After some consideration, I decided to keep ‘Nature’ capitalised in the reverential form that Scott submitted his original copy through to the magazine.