What fish order includes the true eels?

What fish order includes the true eels? The answer is Anguilliformes.

Anguilliformes is the order containing the true eels, including freshwater eels, morays, conger eels, snake eels, garden eels, and many deep-sea forms. The group includes about 1,000 species arranged across roughly 20 families, making it one of the major lineages of elongated ray-finned fishes.

True eels share a distinctive body plan: most lack pelvic fins, many lack pectoral fins, and the dorsal, caudal, and anal fins often form a continuous ribbon around the rear of the body. They swim by sending waves along the length of the body, a motion that can even be reversed to move backward.

Not every fish called an “eel” belongs to Anguilliformes. Electric eels are knifefish, swamp eels belong to Synbranchiformes, slime eels are hagfish, and spiny eels are separate from true eels. Deep-sea saccopharyngiforms were once treated as a separate order, but modern classifications place them within Anguilliformes as a derived lineage. The order name comes from Anguilla, the genus of freshwater eels.