Quote Originally Posted by alex View Post
how looks an "asphyxiated"/exhausted frog? Does the stomach turn pink/red?

maybe because one frog starts to be hyper, it exited the other one, so the other one bites the hyper one (it happens 2-3 times a years, quickly, with no consequence). Maybe the "fight" turned to be almost deadly this time?

Basically, maybe the frog is just exhausted... that would explain the blood drips too.
I would seperate the ill frog from the other. set up a hospital tank with the same temp water, but have something That the frog can climb on to get out of the water. Something is not right and he will need to be watched carefully. I suggest a visit to a vet that specializes in amphibians. I'm not sure what is going on, but the frog is severely stressed. You should post some pictures of both frogs and their setup.