Description: This is the behaviour where some species of fish will visit particular locations known as cleaning stations, to be cleaned of external parasites by other species. The species to be cleaned often exhibit apparently unusual postures, holding themselves vertically for example, remaining still in the water while they allow the cleaner species (fish or prawns) to go over their body removing the parasites. In the Mediterranean, prawns, or juvenile wrasse and adults of some of the smaller wrasse species, can often be observed performing this cleaning function. There are very strange combinations of larger predatory fish remaining still while being cleaned by much smaller species of fish or prawns, which might normally be considered as prey. This behaviour is often seen although not on every dive, more usually over rocky habitats. The video shows a large wrasse moving very slowly while being approached by a range of other much smaller wrasse. The still photo shows a moray eel being cleaned by a shrimp.

Text: Bob Earll
Photo: iStock Photo
Video: Bob Earll