Reef fish are awesome because they come in so many shapes, sizes and colors. This amazing diversity of colors though awesome can be a nightmare for researchers trying to identify them.
The cleaner wrasse co-existing with other reef fish is a perfect example. Cleaner wrasse is a small reef fish that you often see around the reefs. Other than the blue color and a lateral stripe running down its body, nothing really sets this fish apart and sometimes, they go unnoticed among the large reef fish (“bouncers”). However, the Cleaner wrasse lives a very interesting life. They are usually seen alone or in a family of 6-8 individuals with one male. There is a lot of competition and predation in coral reefs and organisms have to look for ways to survive. Cleaner wrasse has devised a strategy to survive.
Cleaner wrasse cleaning a bullet head parrot fish
As the name suggests, Cleaner wrasse clean other fish. They are carnivores feeding on tiny parasites that are found in other larger reef fishes. Instead of hiding or running away from their predators, they live with them by setting up “cleaning stations” where they clean the larger fishes. The males are usually territorial and establish the cleaning station with several females. They perform a “small dance” by moving their tail up and down, to invite the larger fish. The larger fish know this ‘invitation’ and allow the Cleaner wrasse to feed on the parasites and scraps of dead skin on their body. The larger fish in turn provides protection to the Cleaner wrasse.
They begin their life as females and then some change to a male. When a male heading a family dies, a female in the group – usually a bigger one – changes into a male to replace the dead male or set up another family.
The tiny blenny (also a reef fish) mimics the colors and behavior of the Cleaner wrasse to get a free meal. But this notorious little fish bites off pieces of flesh from its unsuspecting “client” instead of cleaning.
Cleaner wrasses are important for healthy coral reefs. However they are over-fished for aquariums even though they do not thrive in aquariums. They die within a few days of captivity because they cannot feed on the parasites and dead skin of the big fish.
When the Cleaner wrasse population goes down, there is danger of parasites increasing on other reef fish leading to an unhealthy reef. So it’s better to leave the Cleaner wrasse with their cleaning stations in the reefs.