If these little fish are obtained through legal channels and are not protected rare species, then you can choose to release them or eat them !
If you choose to release them, the little fish can return to nature and continue to grow and reproduce, contributing to the balance of the ecosystem. If you choose to eat them, there is nothing wrong with it, but make sure to meet food safety requirements during cooking and consumption. However, even if the little fish are not rare and protected species, when deciding whether to eat them, ecological protection factors can also be considered. Try to avoid overfishing and eating wild fish as much as possible to maintain ecological balance !