The genitalia of fish

I found this on the net. It's about how size matters to female fish.

"Male genital size in some fish species may be driven by competing evolutionary mechanisms, reflecting a tradeoff between the capacity to attract mates and the ability to quickly evade predators, US researchers report.

Mosquitofish cannot retract their gonopodia - modified anal fins through which males transfer sperm to females - and they often display or swing them during courtship. In laboratory experiments, females preferred to spend time with videos (is this the first example of piscine porn?) of males displaying digitally enlarged gonopodia rather than those with average-sized gonopodia, which implies sexual selection for increased gonopodium size.

Yet the researchers also found that males with larger gonopodia were slower to escape potential predators through evasive swimming bursts, an effect perhaps due to greater drag in the water. These results suggest that alternative mechanisms, such as mating selection favoring larger genitalia and natural selection favoring reduced size, may also drive genital diversification."

It's good there are scientists, and that they have subjects to study. I can think of fewer worthwhile activities in this world than showing videos of digitally enhanced fish dicks to female fish. This is worthy.