cleaner fish, coral reef cleaner fish
Mila Zinkova
Goatfish, Mulloidichthys flavolineatus at Kona, Hawaii being cleaned by two cleaner Wrasses,
Labroides phthirophagus.

Cleaner Fish “Uniform” Underscores Value of Camouflage in Nature

August 25, 2009 04:00 PM
by Anita Gutierrez-Folch
The different colors and patterns used to distinguish coral reef cleaner fish are an example of protective camouflage found in nature, and used to great benefit by the wearer.

Cleaning Uniforms for Fish

A new study published in the journal Current Biology suggests that cleaner fish living in coral reefs wear “uniforms” that help set them apart from other fish, revealing their “profession” and allowing them to “avoid being eaten by their clients,” Christine Dell’Amore reports for National Geographic.

The relationship between cleaner fish and their clients is a symbiotic one: cleaner fish rid their clients—both predators and prey—of parasites and bacteria, feeding on the waste at the same time. According to New Scientist, cleaner fish often “caress” their clients with their fins to calm them down. As Redouan Bshary of the University of Neuchatel in Switzerland explains, this light touch “makes hunters so mellow that it transforms the cleaning station into a safe haven for other fish.”

The study quoted by National Geographic suggests that “colors and body patterns” of the various species of cleaner fish set them apart from other smaller fish that predators could consider prey. Karen Cheney, biologist at the University of Queensland in Australia, and her colleagues, found that “cleaner fish—such as gobies and wrasses—are more likely to sport a dark side stripe accentuated by patches of blue and yellow” that differentiates them from other fish, making them “conspicuous and easy to distinguish on a coral reef.”

By investigating the different species present in Australia’s Great Barrier Coral Reef, Cheney and her team also found that those fish “painted with blue colors and striped body patterns enticed more clients to pull up to a cleaning station,” since their color contrasted with the surrounding reef and made them more visible. According to Cheney, the “uniforms” worn by the cleaner fish evolved after their cleaning behavior, possibly becoming more common as they attracted more clients and helped avoid predation.

Background: Camouflage in nature

Many different species in the natural world make use of camouflage or disguise for a variety of purposes, be it protection or predation. As Encyclopedia Britannica explains, there are many types of camouflage, including background matching, color changing, disruptive coloration and countershading, “in which the upper surfaces of an animal’s body are more darkly pigmented than the lower areas.”

ENature highlights a series of species that make use of camouflage to blend into their surroundings, such as snakes that merge into the sands of the desert, salamanders that pass as lichen, lizards that fade into their rocky surroundings and even a caterpillar that can make itself look like a “large bird dropping” in order to fend off predators. At the same time, predators such as the polar bear, the white shark and the goosefish use camouflage as a predatory aid, giving them the element of surprise as an advantage when attacking unsuspecting prey.

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