No.51 Japanese eel catfish

Gonzui is a member of the catfish family that inhabits coastal areas, rocky reefs, and sandy-muddy bottoms throughout Japan. It is nocturnal and feeds by sucking up polychaetes and small crustaceans from sandy bottoms. The tips of its dorsal and pectoral fins have sharp poisonous spines, and being stung causes severe pain and swelling. Juveniles form schools and, when sensing danger, create spherical groups known as “Gonzu balls.”Translated with DeepL.com (free version)

This sample was requested by NHK Enterprises, Inc. and CT scans were conducted as a project for NHK E-television's “Gyogyotto Sakana★Star”.
Gyogyotto Sakana★Star" program HP: https://www.nhk.jp/p/ts/P58QMGP4K1/

CT scan revealed that the bones around the jaw and cheekbones are structured to allow the mouth to open and close quickly.The two white circles lined up on the head are otoliths, which are involved in balance and hearing. They are made of calcium carbonate and are denser than bone, so they appear as clear white circles on a CT scan.