Help! I'm having trouble identifying a disease in one of my neon tetras. I thought it might be neon tetra disease but he is acting normally, schooling with the rest and eating. The water parameters are good and the same group of fish (tetras and some fancy guppies) have been in the tank for about 9 months now (no new additions). His scales started appearing "rough" a few weeks ago and I've now isolated him in a quarantine tank with saline. It looks like its progressing slowly but his behaviour is still normal. Any suggestions?