Eel

Eels are ray-finned fish of the order Anguilliformes, comprising eight suborders, 20 families, 164 genera and about 1,000 species, developing from transparent larvae into adult predators; the name eel is also loosely applied to unrelated fish such as electric eels and deep-sea spiny eels that evolved a similar body shape independently. True eels range from 5 centimeters in the smallest species to 4 meters in the slender giant moray, most lacking pelvic fins and many lacking pectoral fins, with dorsal and anal fins fused into a ribbon running along the body that lets them swim with wave-like motion and reverse direction. Most eels are marine and nocturnal, burrowing into sand or rock in shallow water, though the genus Anguilla lives in freshwater and migrates to the ocean to spawn. They are prized in Asian cuisine, eaten as unagi, freshwater eel, and anago, marine eel, in Japan, including in the expensive unadon dish, and valued highly in Chinese cuisine, with Hong Kong prices once exceeding 5,000 Hong Kong dollars per kilogram, while Europe eats them as jellied or smoked eel; the European eel is critically endangered and the American and Japanese eels are endangered.