neons swimming funny
I know it's been addressed here before but I didn't see many solutions in the posts I found so I wanted to ask again...
I have 10 neon tetras, and at least 1 has something wrong with it. He's swimming with his nose pointed at a downward angle, kind of twitching along instead of swimming fluidly. His stomach is big and round. I say at least 1 because there are a couple I'm not sure if they're starting to do this or if I'm being paranoid. I just got back from a trip so I didn't see this develop.
He's not white, his scales look fine, the ammonia, nitrite, and nitrate levels are great. He and all of my fish are eating fine, and all of their color is bright.
I guess I'd like to know what he has, how to treat him, and if I possibly have to euthanize to avoid losing all of them. I don't have a hospital tank (I don't know where I'd even put one.)
Also, if he's sick, will it spread to other species---I have harlequin rasboras, albino cories, and upside down cats.