Thanks Jancy. The frog is back to normal now, actually he was lunging at the other cories as soon as I put him back in the tank (I've removed them since then). Also thankfully the cory appeared to already be dead before I had to deal with it, or that would have been even worse. I definitely have to agree with a 'species only' tank now, turns out there are more issues than aggressive fish.

I put some polysporin on the frogs chin and didn't have to do much else, luckily the fin poked straight through like a small needle and didn't cause any hemorrhage. Thankfully I was familiar with the protocol after I accidentally cut my other frog's leg this summer. My poor frogs are really taking a beating from my lack of experience...