Pale, spastic, not eating, and limp?

[Ligeia]

I have had my betta for probably 4-5 months and he has always been very healthy and active. But about 2 weeks ago, he started not eating his food and he would just lay limp on the bottom or top of his tank. Then I started noticing that he TRIES to eat but he can't seem to get control of himself to actually get the food. After trying for a minute to get his food, he just starts spazzing all over the tank hitting the walls and acting like he can't control himself until he finally just settles back on the bottom of the tank. He is looking pretty pale and limp now after this has gone on for a while. There weren't any food or environment changes recently so this is a total mystery to me. He acts like he has brain damage.

[Oldfishlady]

Sorry you are having problems, have a few questions so we can better help you....

How big is the tank, filtration if any
How much and how often are the water changes and when was the last one?
Any additives used, if so, what kind, what for, how much
Water temp?