AFP - Among some cleaner fish species, it appears that it is the males who are more devious than the females, a researcher at the University of Neuchatel in Switzerland has found.

By protecting their clients from being bitten by overzealous female cleaner fishes, the males bag for themselves some tasty dessert.

The cleaner fish Labroides dimidiatus, which measures about 10 centimetres (four inches), feeds on parasites found on larger fishes.

But the females can sometimes be too greedy and "bite the flesh of the fish they are cleaning in a bid to get to the mucus, which is more tasty than the parasites on the surface," researcher Redouan Bshary found.

The male fishes, which are bigger in size, would then step in to chase the females away.

By protecting the fish they are cleaning from being bitten by the female cleaners, the male cleaners keep the client from leaving the cleaning station.

Fearful of incurring the wrath of the males again, the females also no longer dare to go near the mucus.

After the cleaning is done on the surface, the males can then move on to the mucus for dessert, without having to share it with the females.

The male fish is therefore the "main winner," said the researcher, whose findings are published in the journal Science.