Some fish feed on parasites on the bodies of other fish and are collectively called "cleaner fish." Bluestreak Cleaner Wrasse is a well-known cleaner fish, belonging to the wrasse family that inhabits coral reefs and warm rocky areas in the Indian and Pacific Oceans.


Bluestreak Cleaner Wrasse
At Tokyo Sea Life Park 's "World Oceans" area, the "South China Sea" tank displays Bluestreak Cleaner Wrasse alongside large fish such as Humphead Wrasse and Napoleon wrasse. Many of the fish in this tank are several times, even tens of times, larger than Bluestreak Cleaner Wrasse, so you might worry that Bluestreak Cleaner Wrasse will be eaten, but this rarely happens.

Bluestreak Cleaner Wrasse sometimes swim by bobbing their tail fins up and down, almost leaping. This swimming style actually signals, "I'm a fish that eats (cleanses) parasites off your body." When other fish see this swimming style, they gather around to be cleaned. However, the fish in this tank seem to know that Bluestreak Cleaner Wrasse will clean them, and they gather around even without seeing its distinctive swimming style.


Black butterfly getting cleaned
In the "South China Sea" tank, you can often observe Bluestreak Cleaner Wrasse wrasses cleaning their owners a little before 8 a.m. They nudge and clean the bodies and gills of other fish in the same tank, such as surgeonfish and sweetlips. The large giant grouper, in particular, open their big mouths wide when their gills are being cleaned, and they seem to enjoy it very much.


A giant grouper having its gills cleaned.
During the morning cleaning time, fish come and go one after another. Bluestreak Cleaner Wrasse is a very popular cleaner in the tank. If you're lucky, you can observe the cleaning even during opening hours.

[Shuta Endo, Animal Care and Exhibition Staff, Tokyo Sea Life Park]

(February 26, 2016)