My youngest axie, Spike, has a problem with his gills. One of the gill "stalks" has been damaged and is hanging by a thread, and the other two "stalks" seem to be pushed flat against his body (gills in left of picture). I don't know what could have caused this, however he does live with two other axies, though they've never been aggressive to each other. My questions are, is there any other cause to this type of injury other than trauma, and what might I need to be doing to help him recover? Or is it just a matter of waiting for him to heal?