Cleaner shrimp is a broad category of crustaceans that refers to any decapod that lives off a symbiotic relationship cleaning other fish of parasites and necrotic material. There are hundreds of individual species that are widely grouped into three taxonomic families: Palaemonidae, Hippolytidae, and Stenopodidae. Each of these families is biologically unique but they fulfill similar roles within the undersea ecosystem afforded to them, usually by warm, tropical waters in which they can thrive. It is not uncommon for them to gather together into cleaning stations and advertise their services to fish passing by.
Cleaner shrimp of all varieties have a tendency to gather into cleaning stations where they can make passing fish aware of their presence. Fish that are in need of cleaning will stop at the station and let the various shrimp located there get to work on ridding their scales of harmful parasites. One of the common advertisement methods is a kind of rocking dance that many shrimp perform- it has been shown that hungrier shrimp perform this side-to-side rocking movement faster than those who have been recently satisfied, and that fish recognize this and go for the ones that promise the best service.
While the three families that make up the group we call cleaner shrimp all work together to fulfill this important ecological function, they carry a number of unique functions between themselves. Particularly worthy of note is the family Stenopodidae, which consists of species that are actually closer related to lobsters and crabs than to true shrimp. Because of this biological difference, it is not uncommon for the term “cleaner shrimp” to more specifically refer to Hippolytidae species of the genus lysmata, which are by far the most common.
In the highly varied habitat of a coral reef, cleaner shrimp occupy a very important point of balance for the ecosystem. The health of the cleaner shrimp population is crucial for the proliferation both of their predators and the fish that they share a symbiotic relationship with. Their importance is largely due to the fact that their cleaning habits keep the other fish healthy and allow for greater biodiversity within the area while, from the point of view of their predators, the shrimp are often the only food source available.