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).