Biology
Icosteus aenigmaticus, (Lockington, 1880), 112mm large juvenile specimen (UW 041565).
Juvenile ragfish differ remarkably from adults.
Juveniles are light brown in colour and sprinkled with dark spots. They have a rounded caudal fin and pelvic fins below the pectoral fins.
During development the colour changes to a dark chocolate brown, the pelvics disappear and the caudal fin changes to a forked appearance.
It is believed that juvenile ragfish feed on medusa and jellyfish. Stomach contents of adult ragfish revealed additionally cephalopods, salps, and small fishes such as eel pouts (Zoarcidae).