Golden Ram Getting Old?

I have had this golden ram for about 9 months or so and when I got him he was nearly full size. Well for about the last 2 weeks he has slowly become less active and lately has just been hanging in the bottom of the tank in a corner. He still eats, has good coloring, and will fight my other male ram when he gets close. I can't think of any diseases he might have and I know that rams don't usually live past 2 years. I was wondering if this is what happens when fish are getting old and in fact could this be happening to my ram?

Well I don't know what it was but he has been getting better. He is almost acting like his old self again. I noticed that he lost his territory and this may be why he was acting weird. He might have been depressed about losing his territory and not being the alpha male anymore.