I posted a similar question on Yahoo! Answers, but got only one sort of vague response, so I figured I would ask it on a site dedicated to aquariums and general fish keeping. I've been meaning to join this forum anyway, since I have a planted tank and use information from the site often! Anyway, everything was normal when I turned on the lights this morning. Everyone was happy and hungry (I feed my fish once per day). I suppose I should start with my stock:
-9 Neons (I know that Angels can be aggressive to neons, but there haven't been any problems in all the months he has been kept with tetras, and the tank has quite a bit of free space)
-4 Rasboras (used to be 5, I'll get to that)
-3 mystery snails
-4 ghost shrimp
Okay, sorry for the long intro there, getting on to the situation that has me panicking. So, everything was perfectly normal when I turned on the lights this morning and fed them. Everyone ate normally and nothing was left over. I had to go out most of the day, so I wasn't there to monitor the tank. After getting home I went to check on my tank and I noticed one of the rasboras looked in really bad shape. REALLY bad shape. His back was all crooked and he wasn't schooling as he normally does with the rest of the rasboras. His coloration looked a bit off, a little pale, but not so much that it was alarming. I didn't notice any bulges on him. He was also staying near the top of the water, but not gasping for air at all.
After a while of watching him, I could see his condition was worsening and worsening, so I decided to humanely put him out of his misery (the whole freezer deal) :/ What could this have been? Please help me. I don't want my other fish to catch it if it is contagious. What astounds me is that everything was perfect 7 1/2 hours prior to finding him like that. Thank you for your time.