If male mosquitofish could choose the size of their genitals what would they do?
The dilema comes from the tradeoff between mating and being eaten. Bigger genitals attract females for mating, but they drag in the water and slow down males trying to avoid being eaten.
Unlike most fish, male mosquitofish swing or display their prominent genitals (called gonopodia) during courtship, and females watch carefully and choose males with bigger genitals. But the big winners in the dating game may not live long enough to appreciate their success, since bigger genitals make it harder to escape predators.