Random Bits: Filamentous Algae Self-Sustaining Aquarium

I started cultivating filamentous algae in my oldest 1.6 liter aquarium.

Here it is, on the left, back in 2016.

Also, I experiment with filamentous algae in plastic bottle nurseries to see if it can be used in self-sustaining aquariums with fish.

Here is a hair-thin string of filamentous algae.
Filamentous algae grows in long strings.

It grows in the widest range of conditions.
I have it growing exposed to direct sunlight in water temperature above 90F.

I found filamentous algae growing in running streams and still water in ponds of Central Park NYC all year around, even under ice.

Here, I am breaking the ice to get a sample of filamentous algae.
All samples of filamentous algae come with critters.
It serves as a place to hide and as a food for them.

Filamentous algae grows extremely fast creating a mesh that takes over a space of any size aquarium, from a tiny string you may not even be able to see at first.
Filamentous algae is very intrusive!

It has to be cut to a desirable size as necessary.
Here I remove half of the mesh.

The remaining half takes the same space in the aquarium as though I did not cut it at all.

Here is a more visual example.
I put what looks like a very little amount of filamentous algae in a cup.

Now, let's add water.

The mesh of algae instantly takes over the entire available space.
Give it time and it will grow more dense.

Previously, I established that my dwarf guppies feed on filamentous algae.

Then I setup nurseries to check if filamentous algae grows fast enough to provide sufficient food for breeding families of guppies.

I also put other plants, snails, and seed shrimp in each aquarium.
So, there would be different types of food available for my guppies.
And I would not have to feed them at all ;)

Long story short - the filamentous algae grows faster than my guppies can eat it.
Here you can see nurseries with different amounts of filamentous algae.

Seed shrimp hide from fish and breed in the thicket of filamentous algae.

Guppies nibble on filamentous algae and hunt seed shrimp that venture out of the protective mesh.

Here is a closeup view.
Notice how the fish moves through the thin mesh.

Now it swims in free water.

For the purpose of the experiment, I let filamentous algae grow as much as it could.
Filamentous algae grows in a thick mesh taking up all available space and leaving no room for guppies to swim.

The thick mesh of filamentous algae became a death trap for any fish, even strong adult fish, entrapped in it.

It became obvious that this type of filamentous algae, as much as I like it, cannot be used in my self-sustaining aquariums.

At the end of this experiment, I transfered fish and disassembled the used nurseries.
The end of this experiment is the beginning of another one ;)

Actually a number of experiments :)

I build new generations of self-sustaining aquarium gardens, in which I experiment with a different type of filamentous algae better known as Marimo ball.