Answer:

EEL

Answer	Crossword Clue
EEL	Conger
EEL	Electric swimmer
EEL	Fish sans pelvic fins

EEL	Lamprey
EEL	Long swimmer
EEL	Moray
EEL	Slippery customer
EEL	Slippery fish
EEL	Slithery fish
EEL	Smoked delicacy
EEL	Sushi morsel

EEL	Cave-dwelling fish
EEL	Elder elver
EEL	Grown-up elver
EEL	Scaleless fish
EEL	Scaleless swimmer
EEL	Sea shocker
EEL	Slithery swimmer
EEL	Sushi snack

EEL	Elver's elder
EEL	Foal:horse::elver:
EEL	Kingklip
EEL	Sargasso serpent
EEL	Slippery one
EEL	Sushi staple
EEL	Slippery sea spawner
EEL	Dragon roll component

EEL	Finless fish forbidden in kosher diets
EEL	Escalator's snakelike counterpart in a "SpongeBob SquarePants" game
EEL	Pickled delicacy
EEL	Slippery creature
EEL	Sushi bar choice
EEL	Flexible fish
EEL	Migratory fish
EEL	Sushi fish

EEL	Smorgasbord fish
EEL	Elusive one
EEL	Moray, e.g.
EEL	Electric creature
EEL	Wriggler