Which freshwater fish is commonly called the Chinese algae eater in the aquarium trade?

The aquarium fish commonly called the Chinese algae eater is Gyrinocheilus aymonieri.

Gyrinocheilus aymonieri is a freshwater fish native to mainland Southeast Asia, including parts of the Mekong, Chao Phraya, and other river systems. It is sold in aquariums because young individuals often rasp algae from surfaces using a specialised sucker-like mouth.

The common name can be misleading. As the fish grows, it may become less useful as an algae cleaner and can become territorial or aggressive toward tank mates. Adult fish also eat more animal and prepared foods, so the label does not describe the full adult diet.

Chinese algae eaters are frequently confused with Siamese algae eaters, which belong to the genus Crossocheilus. They are also sold alongside plecos, but plecos are loricariid catfish and are not close scientific matches for Gyrinocheilus.