Anguilliformity

Anguilliformity is a morphological pattern in fishes, named for and typified by the eels. Anguilliform fish have a long, slender body, and travel by anguilliform motion. The caudal fin is often emphasized, with the other fins reduced, absent, or fused with the caudal fin. Anguilliformity has evolved independently in many groups, including among others:

• Anguilliformes, the eels
• Synbranchiformes, the swamp eels
• Clariidae, the airbreathing catfishes
• Dipnoi, the lungfishes
• Cobitidae, the loaches
• Gymnotidae, the knifefishes, including the electric eel Electrophorus electricus