No.34 Japanese Eel

Belonging to the eel family, Eelidae, they live in rivers, lakes, and shallows with warmer water temperatures, and they prefer to live in tight places such as crevices between rocks.

When they live in rivers and lakes, they are called yellow eels because their bodies appear yellowish, and when they grow up and move to the sea to spawn, they are called silver eels because their body color turns black and looks silver.

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

CT imaging revealed that yellow eels have teeth, but silver eels do not. It is thought that they lost their teeth because they did not eat anything during their swim to the waters of the Mariana Islands, some 3,000 km away from Japan, to spawn.