Whats wrong with my betta? Professionals only.?

I just got my betta yesterday and even when i was at the pet shop i noticed there was something wrong, but i thought what the heck if i don't take care of it no one else would. Why not give it a chance at life? So i took it home and put it in my 55 gallon community tank. He didn't bother anyone and they didn't bother him. They were guppies. I treated the tank with meds cause it seems like he has a swimming bladder disease or something. but soon after i put him in a vase with the same water from the tank, afraid that he wouldn't get his food, but he wont eat still. And when he swims he cant just hover there like other fish hes got to use his whole body, but most of the time he props himself up with his fins on an ornament or the gravel and if hes not leaning on something he falls over then tries it again. but every now and then he'll gather his strength to swim around normally for a while. So can anyone help me without leaving stupid comments like just flush him or leave him alone or he planning on taking over the world or hes dead. man i could go on and on with stupid comments. Just please don't leave anything like that. Its disrespectfull and also inhumane to flush it down the toilet.