So, I think one of my older bettas has SBD. The thing is, I'm not sure, because I skipped a meal the day before and I never feed them too much. All the conditions in the tank have been the same. I noticed when I came home from school today that he has been floating on the top of the tank sideways. He tries to swim back down but he just floats back up. After about 1 hour hes given up trying to swim down and now hes just floating on the top. If this is SBD can it be fatal on an old betta? And how can I cure it?