I have no idea what to do. I have only had him since about March 2010 but he has seemed pretty healthy up until a month ago. His fins started to rot and recede and now he is a lot paler than he used to be. He used to be a vibrant red and in certain light he would shimmer blue. Now he barely moves and rests up at the surface. He has a small filter and heater for tanks under 10 gallons. The heater keeps it between 75-78 and the outside thermometer always says its between 74-76. I had been giving him Melafix and that seemed to work for a while. I never really see him eat, he will just hover below the surface with the food touching his face. And recently I noticed that it looks like the flesh around his eye and forehead is getting eaten away. I am so worried and I really don't want him to die but it looks like he is suffering a lot.
I have included some photos of Turtle
Please help me I don't know what to do.