Hi, I have a serpae tetra who is three years old and has been with us since we started the tank. About 2 weeks ago he started skimming the surface. We thought it was an oxygen problem, so we added some aeration to the tank. His symptoms started to become like that of swim bladder disease. I treated him with Epsom salt baths for 5 days, but he stayed the same. He is now constantly swimming around at the surface which is completely unlike him, and he looks miserable. We might euthanize him but wanted to make sure there's nothing else we can do for him.