Good morning all, I really can't seem to catch a break with my fish...two weeks ago one of my platies died under mysterious circumstances, and now one of my Bettas is showing mysterious pale spots on various parts of his body. Because of finals starting two weeks from now and work, I've been awfully busy, meaning that I haven't been able to keep a closer eye on my fish, but I noticed that my betta had a pale spot near his top fin about three weeks ago. He's a double tail betta and his body is slightly bent at that angle where the pale spot was, so I just brushed it off as the light not reaching that portion of his body. However, the pale spot has grown significantly since then, and now I'm getting worried, and I don't know what could be causing it. For behavior changes, I noticed that he eats when I'm watching him and close to his tank, but when I turn around or walk away he stops, despite food still being at the top of the water. He's always been a bit lazy, but he's gotten a bit more lethargic the last few weeks, which is also worrying me. Sometimes he sits at the bottom, while other times he hangs out on a leaf that's near the top of the tank. Here are some pics I took of him before leaving for work. I don't have water parameters at the moment (I was running late for work and could not get them in time) but I do 20% water changes weekly and use 1/2 teaspoon per gallon of API aquarium salt in his tank. He lives alone in a 5.5 gallon tank that is filtered and heated, and the only tools for his tank that is shared with another tank is a gravel vacuum. Can anyone tell me what is wrong with my fish?