trout

Any of several species of fish in Salmonidae, closely related to salmon, and distinguished by spawning more than once.

“Many anglers consider trout to be the archetypical quarry.”

An objectionable elderly woman.

“Look, you silly old trout, you can't keep bringing home cats! You can't afford the ones you have!”

To (figuratively) slap someone with a slimy, stinky, wet trout; to admonish jocularly.