They say that all’s fair in love and war, and that certainly seems to be true in the case of Atlantic mollies (Poecilia mexicana). In their quest to find the best mates, these small and unassuming freshwater fish rely on deceit and Machiavellian misdirection.

A study at the University of Potsdam revealed that the males always prefer larger females - but not if they’re being watched. If they realise that they’re under the gaze of a rival male, Atlantic mollies will either pretend to be disinterested or turn their attention toward smaller (and therefore less attractive) females.

Scientist first thought that the would-be suitors were cowed by the presence of another, bigger male and thus intimidated into courting only their second-best choice of female. But further study revealed that the size of the rival had no effect, with the same behaviour being displayed even when similarly-sized males were around.

This may be the first instance of one male tricking another about which mate they fancy the most – at least in the animal kingdom – and it seems that this kind of deception is designed to divert unwanted attention away from their mate of choice and thus dilute the competition without having to resort to a physical confrontation.