A peculiar fish that is easily recognised by its circular body shape and two protruding fins. Lacks a spine and has an extremely short spinal cord (less than the length of the brain).

Distributed throughout most warm oceans, seen and occasionally found stranded south of Cook Strait in the summer months.

Feeds solely on jellyfish and salps.

Not common and little is known about them.

A Treasury of New Zealand Fishes: Graham