A few hours ago I did a 100% water change because I was treating my friends betta for fin rot, I fed him "Nutrafin Betta food" in the morning I fed him 3 of these, and then to calm him down after a 100% water change around 7PM I fed him 1 extra "Nutrafin Betta food" now when I turned on the light, I noticed when he tries to swim down he floats back to the top, he has a bloated belly small but he didn't have this before, it's like he's been eating stuff in the tank. When I put my hand over the tank it really spooked him out, he swam so fast for 2 - 8 seconds and it was like he was shaking?
Please help, and I hope I didn't overfed him this never happened, this is the second time this happen but last time I only gave him 2 - 3 flakes? This is my friends betta, I am only taking care of him until her tank cycles and until she really fixes up her tank. He sometimes go sideways, I hope he isn't dying :(