Which fish runs its own “car wash”?

If you saw a smaller fish inside the mouth of a large fish with sharp teeth, what would you expect to happen? You might think that the small fish is one gulp away from becoming dinner, and in most cases that’s exactly what would happen. But there are a few lucky types of fish who can get away with it, because they’re actually cleaners.

Wrasses are fish that live in the warm waters of coral reefs. A wrasse sets up a cleaning station, and do tail dipping dances above their stations to attract “customers” and advertise that they’re open for business. When a larger fish wants to be cleaned, it swims to the cleaning station and stiffens in order to let the wrasse do its work.

The wrasse swims around the fish devouring parasites, dead tissue from wounds, and even swims inside the larger fish’s mouth and gills to remove harmful tissue. This benefits the larger fish by keeping it clean and healthy, and the wrasse gets a good meal. Though rarely a larger fish forgets itself and swallows the wrasse, this actually doesn’t happen very often.

In fact, the cleaning relationship is so useful that another species of fish called a blenny has evolved colours and movements that mimic the wrasse. When an unsuspecting fish approaches for a cleaning by a friendly wrasse, the blenny nips in and bites off a piece of flesh!