You should release them. In many areas, it is illegal to capture and keep wild animals. Additionally, frogs and toads have different needs. If you don't know which you have, how do you know your tank is a proper environment? They'll be much happier back in the creek where they can eat, hop, and reproduce as they please.

Maybe do some research, I'd suggest flies and crickets.

Any and all types of bugs.

I found 3 brown toads/frogs (idk the difference) in the creek about a week ago and I have them as pets now, i have the proper tank and stuff with water and everything but i just want to know what do they eat? I fed them a grasshopper and a few snails and yeah i really dont know!