try feeding him in a bucket or small tank. this way hes defintly getting his food at least. as for the possible injuries, Id have to say probably not but then again, how big is you fish? if the fish is big enough to partly 'eat' the baby's leg, then maybe its not such a good idea.
I kept my southern in a large goldfish tank for a while. the fish never bothered him. THe only fish that even went near him was the Plecostomus, and that was to eat the algae on the turtle dock. hes living alone nowadays, and he seems healthier. I was very concerned that the goldfish might attempt to take his food, so I always fed him separetly.

Good luck