While many other fish—such as electric eels and swamp eels—have evolved similar elongated shapes, they belong to different taxonomic orders and are not "true" eels.
The oldest fossil record of a living true eel lineage ... - bioRxiv anguilliformes
: Most species have a snakelike appearance with a complete absence of pelvic fins . Their dorsal, anal, and caudal fins are often continuous, forming a single fringe around the tail. While many other fish—such as electric eels and
True eels are found globally in a vast range of aquatic environments: and caudal fins are often continuous
: The majority are marine, inhabiting everything from shallow coral reefs (like moray eels ) to the abyssal zone (like gulper eels ).