my flower horn has become black from one side of its head. its also acting wierd and ramming into the glass and eating and spitting the stones from down. ive posted its picture pls help me....

looks like it is fading buddy, nothing to worry about IMO. It should have really cool colors when it loses the black. This is normal for fading fish. Not very rare, but not real common either. Sometimes the fading process goes real fast, sometimes it takes a long time. Sometimes it will fade 100% sometimes some black spots will reamain. Time will tell.

i've heard of fish getting pinched nerve or veins and thus causing the black color. i haven't had this happen to me or do i know how you can treat it. roundhead might be able to help you farther on this.