Botanicals in Freshwater Aquariums: Creating a Natural Ecosystem

A freshwater aquarium doesn't have to be just water, fish, plants, and filtration. In many natural aquatic environments, the bottom is covered with fallen leaves, seed pods, branches, bark, and other plant material. These botanicals gradually interact with the water and become part of the ecosystem itself.

Adding botanicals to an aquarium is a way to recreate some of those natural processes while providing structure, cover, and additional surfaces for biological activity.

What Are Aquarium Botanicals?

Aquarium botanicals are naturally derived plant materials selected for use in aquatic environments. They can include dried leaves, seed pods, cones, bark, palm material, roots, and other plant structures.

Different botanicals behave differently once submerged. Some release significant amounts of tannins, while others contribute very little coloration. Some break down relatively quickly, while thicker pods, bark, and woody materials can remain in an aquarium for considerably longer.

This makes botanicals useful for much more than simply creating a particular look.

Tannins and the Natural Aquarium

One of the most noticeable effects of many botanicals is the release of tannins into the water.

Depending on the botanical and the amount used, these compounds can give aquarium water anything from a very subtle yellow tint to the deep tea-colored appearance associated with blackwater environments.

Not every botanical produces the same amount or color of tannins. This allows aquarists to choose materials based on both the ecosystem they are trying to create and the appearance they want.

Botanicals Become Living Surfaces

Once submerged, botanicals begin to be colonized by microorganisms.

One of the most visible results is biofilm. This may appear as a white or translucent coating on leaves, pods, wood, and other organic material. While it can initially surprise aquarists who haven't used botanicals before, biofilm is an expected part of the decomposition and microbial colonization process.

These colonized surfaces can also become grazing areas for shrimp, other invertebrates, and some small fish.

Instead of thinking of a leaf or seed pod as an inert aquarium decoration, it is more useful to think of it as another surface within the aquarium's developing ecosystem.

Creating Structure and Habitat

Botanicals can also physically change an aquarium.

Leaves create litter beds. Seed pods and larger botanical structures can provide cover and small cavities. Twigs, roots, palm material, and other botanicals can add complexity at substrate level.

That structure can be especially useful when creating naturalistic environments for animals that spend significant amounts of time close to the substrate, among leaf litter, or around submerged plant material.

At Nu Aqua, this is one of the things we find most interesting about botanicals: they allow an aquarist to build an environment rather than simply decorate a tank.

Blackwater and Biotope-Inspired Aquariums

Botanicals are particularly useful in blackwater and biotope-inspired aquariums.

Natural aquatic habitats aren't sterile environments. Plant material falls into the water, becomes saturated, releases soluble compounds, develops microbial communities, and eventually decomposes.

Using carefully selected botanicals allows us to incorporate some of those processes into an aquarium while also recreating some of the physical characteristics found in natural habitats.

This can be especially useful when keeping fish associated with leaf litter and botanically rich environments, including many bettas, rasboras, gouramis, dwarf cichlids, and other freshwater species.

Start Slowly

Botanicals are organic material, which means adding them also contributes to the biological load of an aquarium.

More is not necessarily better.

Our preparation guidelines recommend beginning with approximately 2–3 pieces per 5 gallons of water, added no more than once per week and between water changes. This gives the aquarium's biological community time to adjust as the material is colonized and begins breaking down.

Shrimp tanks and aquariums containing sensitive species should be started at the lower end of that range.

Before adding botanicals to your aquarium, please read our Botanical Preparation Instructions for complete preparation, soaking, and introduction guidelines.

Building an Ecosystem, Not Just an Aquascape

One of our goals at Nu Aqua is to encourage people to think about an aquarium as a functioning biological system.

Plants, animals, microorganisms, filtration, substrate, water chemistry, and decomposing organic material all interact. Botanicals give aquarists another tool for introducing natural materials and processes into that system.

They can certainly make an aquarium beautiful. But their more interesting role begins after they're underwater.

Nu Aqua is an authorized retail partner of Betta Botanicals. To learn more about the company that sources the botanical products we carry, Shop blackwater aquarium botanicals at Betta Botanicals.