About 2 weeks ago, I bought six neon tetras, once they were in my tank, i realized that one of them continuously had his/her mouth open. My sister did some research and she found out that the same thing happened with someone elses Koi and that it was just a broken jaw but i also read that it could be a disease. So far he's survived 2 weeks and hes happily swimming along with my other tetras and minnows.
