It's crazy how fast amphiuma's can heal, a few day's ago one of the amphiuma's bit the others tail, and the resulting struggle left the one that was bitten first with a badly damaged tail that I thought would end up falling off. The next day I came in and it looked like there had never been a problem with the ones tail beside a slight discoloration! I wish humans healed that fast...
BTW- it is not normal for the amphiuma's to bite each other, one tried to catch a fish, but it missed and ended up biting the others tail, it took a lot of convincing to get it to let go.