I had a single guppy in a 1 gallon tank and today it died. It had been there for around 4 months. I just turned on the light and it was like bent in half almost. Is there some kind of disease that causes a fish to do that? Also the tank was doing some thing weird, it is just an undergravel filter and there was pockets of air being released from under the gravel. The gravel is about 3 inches deep. The air pockets seemed to be being released at a steady rate but I had not noticed it till today. I had just topped the water off about 2 days ago and added the dechlorinator and thats it. Any ideas?? Let me know what you guys think...........