The mouths of these fish have developed into a suckermouth. This allows the fish to cling onto objects in the fast-moving water of their habitat. They therefore stay close to the bottom where their primary food, algae, is more readily available.
Uniquely among fish, members of this family have gill slits with two openings each. Water enters through one opening, and leaves through the other. This allows the fish to breathe without having to take water in through the mouth, which it uses to cling to surfaces. The CAE is sometimes kept inaquaria to control algae. It can range up to 11 inches (28 cm) in length.