It’s called ‘Shirasu’. It’s the juvenile offspring of anchovies, herrings or sardines.
In other parts of the world it’s called ‘whitebait’ or ‘gianchetti’, or…other names. The exact species varies from place to place too.
reference: Wikipedia
It looks like shirasu (or “whitebait”):
Credit:stackoverflow.com‘
4 Mar, 2024
4 Mar, 2024
5 Mar, 2024
5 Mar, 2024