Southern toad help?

I just caught a southern toad that appears healthy just minutes ago. I got the exact enviroment a hiding the substrate that i got from outside for it a couple of leaves, anyway he ate 3 crickets and i caught him just ten minutes ago does that mean he'll be a good captive? he is also in a 19 liter container ( i also dampened the sandish soil and i added a piece of mulch) what can i feed it? every time he eats the cricket it takes him like two minutes to get it into his stomach he gets it down fine though but he moves his belly almost exactly like a snake trying to swallow a mouse. How many times can i feed it a week? Can i catch stuff from outside and please tell me everything else i didn't quite get.