Some male fish let rivals woo females and then hijack their courtship

By Christa Lesté-Lasserre

The dominant males in one species of Amazonian fish have developed a simple way to grab mating opportunities. They stay hidden and watch while smaller, less-dominant males work hard to persuade a female to lay eggs – then they come forward and steal the receptive female’s attention.

Lower-ranking male sailfin tetras (Crenuchus spilurus) put in a lot of time and effort to court females. They may spend several days circling aquatic weeds with their colourful fins extended fully.

Tiago Pires at the National Institute …