Difference between greentail and yellowtail catfish: greentail catfish fins and tail appear greenish in the light and are flatter. Yellowtail catfish has yellowish fins and tail and is wider. The yellowtail catfish is a specialty of the Dongting Lake system in Hunan Province. Both greentail and yellowtail catfish are channel catfish. Channel catfish is a collective name for four species of channel catfish, including fine-scaled channel catfish, yellow-tailed channel catfish, round-nosed channel catfish, and silver channel catfish, belonging to the order Cypriniformes, family Cyprinidae, subfamily Channel Catfish, and genus Channel Catfish. Other local names for channel catfish include: yellow gourami, yellowtail, sand gourami, yellow stripe, yellow river, yellowtail, and Sichuan stripe (the name given to silver catfish and fine-scaled channel catfish in the Sulu region). Channel catfish like to eat rotting mud, organic debris, etc., has a special function of water purification, improve the ecological environment, also known as ecological fish.