WTF!!!

My fish is a betta. I've had it for almost a year. All of a sudden his tail doesnt really work. Like he just lays on the side of the fish tank and doesnt do shit. He moves it a little but not enough to get around anywhere.

Before he use to come swimming up to me and everything everytime he saw me come to the bowl. He just uses his 2 front flippers to struggle to eat food. I dont know whats wrong.

Should I end his misery? Should I let him live? I dont know what to do.

Please my wise IA'ers enlighten me.

I'm serious to about my fish. I'll post pics of him just chillin on the side of the fish bowl later on...I dont know whats up..