Suckerfishes

Suckerfishes is a common name applied to several groups of fishes that share suction-based feeding adaptations. The term most often refers to two distinct lineages: remoras and the freshwater suckers.

Remoras (family Echeneidae) are marine fishes characterized by a distinctive suction disc at the top of their heads, formed by modified dorsal-fin elements. This disc allows them to attach to larger hosts such as sharks, whales, sea turtles, and even ships. Remoras are typically solitary and travel with their hosts, feeding on scraps of food that the host misses and on external parasites or epibionts. They invest little in active swimming and can detach when needed. Remoras inhabit tropical and warm temperate oceans worldwide and include several species, the best known being Echeneis naucrates.

Suckerfishes can also refer to freshwater suckers in the family Catostomidae. These fishes have subterminal or inferior mouths with thick lips adapted for suction against the substrate. They use suction to feed on algae, periphyton, detritus, and small invertebrates scraped from the bottom. Suckers are distributed across North America, Asia, and parts of Europe, mainly in rivers and lakes and often as important components of stream ecosystems. They vary in size and shape, with some species adapted to fast-flowing waters and others to deeper habitats. Conservation status varies by species and region.

The term suckerfish thus describes two ecologically distinct groups united by a suction-feeding habit rather than a close evolutionary relationship. Both groups illustrate convergent adaptations to grazing surfaces or adhering to larger animals.