Japanese Striped Eel Catfish (Plotosus japonicus) ゴンズイ – size 18cm
Juvenile Japanese Striped Eel Catfish form dense schools that move around like a dark blob. They also have venomous spines so best not to touch. There is also a Striped Eel Catfish (Plotosus lineatus) ミナミゴンズイ which lacks the yellow around the mouth. Gozashirahama 2008