Jimi,
I've been feeding talapia to mine since they were quarter size. But talapia is just the meat. I figure if the only reason people do not feed rodents is the mammal flesh, than fish should work really well. If you feed smelt that have the bones / scales /meat and everything than it should be as nutritious as a rodent but digestible for the frog!

I'm really sold on feeding full smelt, but I'm just worried that if the fish is salted to preserve it it my make the frog hypertonic lol