HELP! sick betta fish?

For the past month my betta fish has been hiding at the back the filter, I don't know if he is eating or not, or coming out. I try to get him to move so he can get hold of some excercise, but i've noticed that his color has faded a lot and his fins look really scruffy. I've got a 2.5 gallon aquarium and the temperature is at a constant 75 degree. So what's wrong with him?
okay it sounds like you have a dieing betta im sure its antiquated and slowly passing away sorry but that's the cycle of life
Whats the best track to preserve my...

Is there anything i can do to keep it alive and well? i've only had it for almost a year.turn up the temp to 80f
My raging masculine guppy change color?
Answers:    look at this

http://www.bettatalk.com/betta_diseases.
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