eel
鰻 refers specifically to the eel, a long, snake-like fish.
鰻 combines 魚 (fish) with 曼, which likely contributes the sound. The character was created to represent the eel, a specific type of fish.
The left side is 魚 (fish), and the right side 曼 looks like a long, winding body. Picture a fish with an elongated, twisting shape: that's an eel.
For マン, imagine a man holding a long, slippery eel: man -> マン, and the eel wriggles in his hands.
eel (esp. the Japanese eel, Anguilla japonica)
lamprey; lamprey eel
giant mottled eel (Anguilla marmorata); marbled eel
Japanese eel (Anguilla japonica)
Erabu black-banded sea krait (Laticauda semifasciata)
eel-like sea creature (i.e. saltwater eels, sea snakes, etc.)
Asian swamp eel (Monopterus albus)
electric eel (Electrophorus electricus)
reedfish (Erpetoichthys calabaricus); ropefish
eel going downstream to spawn
pelican eel (Eurypharynx pelecanoides)
elver (type of eel)
whiptail gulper (any gulper eel of family Saccopharyngidae)
eel farming; eel culture
eel (esp. the Japanese eel, Anguilla japonica)
finely sliced eel and cucumber salad, dressed in sake, soy sauce and vinegar
eel restaurant
omelette-wrapped eel; basted, roasted eel wrapped in a rolled omelette
eel trap
broiled eel on rice with green tea poured on top