How Fish Hire a Cleaning Service

It alls comes down to the hiring process and how clients "eavesdrop" to select the most trustworthy cleaners.

The researchers set up an experiment where client fish could observe two cleaners, one dutifully munching away at another client's parasites and another swimming freely near another client.

Taking the cleaner fishes' past performances into account, the clients chose the cooperative, hard-working fish significantly more often than the loafer.

The authors suggest that the client fish establish a rating system for the cleaners they observe and enlist the aid of those that score highly. The finding illustrates that complex social networks exist in the aquatic world and that this type of selective behavior could be the evolutionary roots of altruism and reputation.

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