Rust Brown Flatworm

General information

The Rust Brown Flatworm is a tan, brown, or rust-colored flatworm that belongs to the Family Platyhelminthes. It can grow up to 1/4″, is oval-shaped, and has two tail-like appendages at its posterior part of the body. It is considered a pest in the aquarium especially when it is rich in nutrients, it can grow rapidly and increase in number drastically. 

This acoel feeds mainly on zooxanthellae from coral tissue leading to the corals' destruction. It can also feed on small invertebrates such as copepods and rotifers.

The number of rust brown flatworm increases naturally when the aquarium is nutrient-filled. It can reproduce either sexually (by laying eggs) or asexually (by budding and binary fusion) or fragmentation where new parent organisms are formed from fragments of the body parts of the flatworm.

This flatworm is one of the "diseases" of the aquarium when it is nutrient-rich. The best way to control its propagation is through prevention. The nutrient level in the aquarium must be kept low while the water flow, protein skimming and use of carbon must be increased.

The rust brown flatworm is native from Cuba.

It is sensitive to changes in water chemistry and its life expectancy is short.