Your frog will try to eat every single fish that it can, they get fairly big and could eat a fish which is 4 inches long easy peasy. Your frogs will be at war with those crabs you own as well so if i were you i would have second thoughts on keeping it.

Fish food is not a healthy diet for these frogs too. They need reptomin sticks as a main diet and the occasional wiggly worm or something similar is nice for them