Since you know the source of the crickets (ie farmed for frogs not just field caught and potentially carrying poisons from gardens etc), then they should be safe for the fish. Might have to remove the rear legs though. Just make sure the to only feed the smallest crickets, fish with food jammed in their mouths are not easy to work with. The smaller the fish the harder it is to remove the stuck food.
I get live fly pupae for my birds and people keep asking me if I give them to my fish, I haven't as yet but they would also be a good protein source for fish with smallish mouths.