Betta Fish: Betta fish sluggish, floating sideways, and tank foamimg

Hello my school's animal club got a betta fish last year and we've been keeping him ever since. But recently the tank started to foam A LOT. We did some research and found out ammonia + sponge filter could be causing this so we took out the sponge from the filter. Then the fish started to float sideways (which I do not have a photo of). The water parameters were fine when we last checked (two days ago, foaming was already happening). He also has more torn fin than when we first got him. We do have a running heater and a filter. Two moss balls and gravels as substrates. What I've gathered is it could be either swimming bladder disease or the gill being damaged from ammonia (which I'm not sure about since the parameters were fine). Please help!!

Edit: the water is also really cloudy. We let it sit there though because we've read somewhere it could be just the tank starting to cycle.