I've had my betta, Lyndon, for almost a year and until about a month ago he was very healthy. I keep him in a 1/2 gallon tank with a small artificial silk plant and aquarium gravel on the bottom. I use filtered water from the refrigerator and let it sit overnight before changing the tank. The temperature in the tank is usually 73 degrees and I change his water once a week. I can't use a heater because the smallest one I can find is for tanks 2.5 gallons and larger. A little over a month ago I bought new gravel and the problems seem to have started afterwards. I noticed the water was getting very cloudy so I changed him twice a week. He developed popeye in one eye, so I started treating him with Maracyn 2. After 3 days, it didn't seem to be getting any better, so I bought him a new gallon tank made for bettas with a light and small filter. The light brings the temperature of the water to 76 degrees, but if I turn it off overnight as recommended, it drops to 72-73. I went to a specialty fish store and they gave me something called Betta Revive which says it prevents and controls protozoan, bacterial and fungal diseases. I've now used it for five days and my betta is worse. He still has popeye and now has small white spots on the other eye which I think might be ick, although I don's see spots on any other parts of his body. He's not eating and is very lethargic. I've put him back in his little 1/2 gallon tank where he was always comfortable, went back to using the Maracyn 2 and have added aquarium salt to the water. I'm afraid I'm losing him and hope you have some suggestions that will help.