A relative of puffers, triggerfish, and porcupinefish, the giant ocean sunfish is listed in the Guinness Book of World Records as the heaviest bony fish and the one with the most eggs. Ocean sunfish are exceptionally strong swimmers, and most records of this fish are based on sick specimens, which are easily captured. Occasionally caught with harpoons, ocean sunfish are utilized fresh and in Chinese medicine.
Other Names
headfish, moonfish; Danish/Swedish: klumpfisk; Dutch: maanvis; Finnish: m hk kala; French: môle commun, poisson-lune; German: mondfisch; Greek: fegaró psaro; Icelandic: tunglfiskur; Italian: pesce luna; Norwegian: månefisk; Polish: samoglów; Portuguese: lua, peixe-lua; Spanish: mola, pez cabeza, pez luna, pez sol; Turkish: pervane.
Identification
Appearing to be all head, the ocean sunfish is characterized by its much-reduced and rudderlike caudal fin, which is gently curved and sturdy; it also has long dorsal and anal fins that it swims with by sculling. It lacks a spinous dorsal fin or pelvic fins, and it is dark brownish-gray or gray-blue. It has no scales, a small terminal mouth, leathery skin, and a poorly developed skeleton.
Size
The ocean sunfish can grow to 10 feet long and 11 feet high (including dorsal and anal fins) and can weigh up to 4,400 pounds.
Food
Ocean sunfish feed on zooplankton, eel larvae, and small deep-sea fish, as well as on jellyfish, crustaceans, mollusks, and brittle stars.
Distribution
Found in all oceans except polar seas, the ocean sunfish occurs in the eastern Pacific from British Columbia to Peru and Chile. In the western Atlantic it occurs from Canada to northern South America.
Habitat
Often drifting at the surface while lying on their sides, ocean sunfish may also swim upright and close to the surface with their dorsal fins projecting above the water. They are sluggish in cold water.
