I have two FBTs one bright green of the Oriental variety and one dark brown.

Recently, i noticed that the dark brown toad was swimming only using one of his hind legs, upon closer examination i noticed that a piece of his left hind leg is missing! The leg looks raw, pinkish in color with a small white portion which i suspect is his leg bone/cartilage whatever.

When i saw it, i freaked out, was convinced that the wound was caused by some sort of aggression between the two toads, i bought a new tank and now have the brown toad isolated from the other. He seems to be using his leg a little more, but it still looks pretty nasty.

The toads did not appear to be hostile to eachother in the past, but i didn't want to take any chances. Maybe this is just an infection, not caused by violence between the two?

Other than keeping him well fed and comfortable in his new living arrangement, what should i do?