1. Different places of origin: Catfish are distributed in the Liaohe River, Huaihe River, Yangtze River, Minjiang River to Pearl River and western Korea in eastern China, mainly in the Yangtze River system; Channel catfish is native to North America.
2. Different shapes: squid has a long body, flat side, silvery gray or yellowish, sometimes with black spots, flat head, large mouth and low position, long dorsal fin and anal fin, and slightly rounded caudal fin; Channel catfish is slightly shorter, slightly higher in back, silvery white, larger in head, larger in mouth, higher in position, shorter in dorsal fin and gluteal fin, forked in caudal fin and longer in two forks.