What is "rough fish"

n. Any fish not considered valuable as sport fish nor used as bait or for food.

n. any fish useless for food or sport or even as bait

Rough fish (or the slang trash fish) is a term used by U.S. state agencies and U.S. anglers to describe fish that are less desirable to sport anglers within a limited region. The term usually refers to larger fish species that are not commonly eaten, are too rare to be commonly encountered, or are not sought after by anglers for sporting purposes. Many of these species are very important in the commercial fishing industry, where they make up the bulk of commercial food fish catches in inland fresh waters.