To compensate, the fish then produce more of their own sperm in the nest. “Nest-holding males have to ejaculate again and again after removal of the rival’s sperm,” says Takegaki.

If you've bought or caught a whole fish and aren't sure what to do with it, you're in luck. An expert shares some ...

Chris Clemens of Asotin, Washington, holds a wild steelhead caught and released in the Clearwater River. The intact adipose fin between the dorsal fin and the tail distinguish the fish from ...