Jaguar Cichlid

Question
Hi, I have a Jaguar cichlid I'm not sure how old he is due to the fact that he was given to me the guy that had him before me found him abandoned in a house so there's no real way to tell his age.
He's around 12 inches long I've had him about 3 months now I change his water twice a month and feed him twice a day.
He seemed like a very happy fish until about 2 day's ago when out of no where he started acting like he didn't want to eat he just Lay's at the bottom of his tank and when he dose get up to swim he starts going all crazy swimming around back and forth like another fish is chasing him or something it seems very odd to me since he's the only fish in the tank.
He also keeps his fin on top of his head pinned down.
I'm really worried about him I don't no what could be wrong with him he eats blood worms, crickets, and shrimp.
Any advice would be greatly appreciated.
                                        Thanks Danelle

Answer
Hi,
Can you tell me the water chemistry? It might be an environmental issue like that.
Also, is they anything weird about his appearance, for example, spots, patches, or growths?

Ether way, do a 35% water change, as that helps with just about anything.