Especially those caught with hook and line and not available on the market

• Perch, for example
• Any of numerous small food fishes
• Bluegill or crappie

Wikipedia Word definitions in Wikipedia
A panfish , also spelled pan-fish or pan fish , is an edible game fish that usually doesn't outgrow the size of a frying pan. The term is also commonly used by anglers to refer to any small catch that will fit in a pan, but is large enough to be legal. ...

Wiktionary Word definitions in Wiktionary
n. fish that are suitable for cooking in a frying pan by virtue both of size and taste; '''panfish''' are caught primarily for eating, rather than for sport

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
panfish \panfish\ n. Any of numerous small food fishes; especially those not available on the market. Any of numerous small food fishes taken with hook and line.

WordNet Word definitions in WordNet
n. any of numerous small food fishes; especially those caught with hook and line and not available on the market

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1833, American English, from pan (n.1) + fish (n.).