Plumatella repens

Did you know there are amazing creatures, living in our aquarium that most people are not even aware of? We have already talked about Carchesium, Aelosoma and Actinosphaerium, creatures that play a viable role in maintaining biological equilibrium in our aquariums. Today we will be adding a new addition to this list: Plumatella repens.

What are Plumatella repens?

Plumatella repens are one of the few microscopic aquarium inhabitants that can be seen with the naked eye. They are colony forming animals that can settle on any surface in the aquarium, like wood and rock, plastic, and even on the leaves of plants.


The size of the colony can reach tens of centimeters, but the length of an individual, called a zooid, is only 1-3 mm. The colony enlarges by budding, and the animals can fan out over long distances by laying eggs, which are carried away by the flow of the water. Once settled on the surface, the first individual hatches from the egg and begins to grow and bud, increasing the size of its newly founded colony.

Anatomy & physiology

Plumatella repens belongs to the phylum of Bryozoa, also known as moss animals. The bryozoans look like sessile polychaete worms, which have their own house in which they can quickly retreat to hide from danger. When all is safe, they reopen the corolla to catch food with their tentacles. Each tentacle is equipped with a large number of cilia, to create a flow of water directed at their mouth. This water-flow brings nutrients such as suspended organic particles, single-celled algae, planktonic microorganisms and bacteria, which are their main food.

Dangerous to fish?

Plumatella repens and other bryozoans may enter the aquarium riding along with newly introduced plants and fish. Luckily they pose no danger to the fish in the aquarium. Just make sure to regularly clean your filter, so colonies developing inside the filter system do not proliferate and cause the filter to clog up.


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