i had good success feeding frogs in a commuity tank by sticking some food in a cd case with one side removed( an sanded down to remove any sharp bits).
so only the frogs could get in side to feed the fish did go nuts trying to get the food tho.
the frogs died, in the end i think its was becausei only feed them on blood worms.
i now have four frogs in there own tank, un filtered at the mo. an there doing very well there singing every night an hugging. lol so think there better off on there own!