I'm new to this forum and sad to say that the first post is about a sick fish. I have a 12 G Eclipse tank. I've had it for a few months now with 4 rosy tetras and 2 flaming dwarf gouramis. I recently added an otto to the tank. Yesterday night I noticed that one of my rosy tetras had her eyes bulging out a bit. Upon further inspection, I also noticed that the area around the gills is somewhat red and it also looks a bit fatter. I currently don't have a quarantine tank so I've been giving them antibacterial fish food. I plan to get a hospital/quarantine tank tomorrow. I would really appreciate any advice on what to do next. I also change water in my tank very often since the tank is not that old. At least twice a week. The water is neutral with no nitrate or nitrite detected. The water is soft and I use Prime with every water change.