Cleaner shrimp is a common name for a number of swimming decapod crustaceans that clean other organisms of parasites. Most are found in the families Hippolytidae (including the Pacific cleaner shrimp, Lysmata amboinensis) and Palaemonidae (including the spotted Periclimenes magnificus), though the families Alpheidae, Pandalidae, and Stenopodidae (including the banded coral shrimp, Stenopus hispidus) each contain at least one species of cleaner shrimp. The term "cleaner shrimp" is sometimes used more specifically for the family Hippolytidae and the genus Lysmata.
Cleaner shrimp are so called because they exhibit a cleaning symbiosis with client fish where the shrimp clean parasites from the fish. The fish benefit by having parasites removed from them, and the shrimp gain the nutritional value of the parasites. The shrimp also eat the mucus and parasites around the wounds of injured fish, which reduces infections and helps healing. The action of cleansing further aids the health of client fish by reducing their stress levels. In many coral reefs, cleaner shrimp congregate at cleaning stations. In this behaviour cleaner shrimps are similar to cleaner fish, and sometimes may join with cleaner wrasse and other cleaner fish attending to client fish.