I first noticed my betta start to swim funny a little over 3 weeks ago then he took a drastic turn right after I noticed it and started spinning every time he was trying to swim. It took me a while to set up a quarantine tank for him so it wasn't ready till the next day and I thought he was close to death at that point he kept trying to swim and it lead to him corkscrewing until he had completely exhausted himself and I thought he was just going to die from that and stress. I finally got him in the sick tank with aquarium salts and anti -bacterial. I than fasted him for 3 days trying to clear his system I was fully prepared to have him not eat on the 4th day and that was going to be my indication to humanely euthanize him, but I was so happy when he ate (I've been feeding freeze dried daphnia). He got more active when it was feeding time but mostly stayed behind his heater for hours. After about 3 weeks of no more real improvement I decided to put him back in his tank (he seemed to hate the quarantine tank since it was empty besides the equipment). He moved around more but still was not his active self lying down for hours on end and sometimes in weird positions. He still swims slightly sideways and he is very floaty seeming to float upwards on his tail end so a lot of the times he'll end up vertical. He barely uses his tail fins to swim anymore mostly just using his pectoral fins to due everything. When he goes up to gulp air I've noticed instead of the one time he usually gulps he'll take 2 and the air seems to push right out of his gills as he gulps it which never happened before. Another thing is all throughout quarantine he never pooped a lot maybe once every couple days so I'm not sure if he's really clearing his system. The last thing that's really worrying me is I've noticed he has started to lose scales on his head and I have no idea what's causing it. Please anyone who has more experience dealing with sick bettas I could really use some help.
There might be and underlying cause with my cycle but I don't know what's causing it nothing I look up helps, I can't seem to get my nitrites down. I have 0ppm ammonia and 5.0ppm nitrates but .25ppm nitrite. Here's everything I add to my tank Easy green fertilizer, Flourish excel, Fritz Zyme trace elements, and a wonder shell once a month for my snail. The Excel and wonder shell are the most recent additions so I'm not sure if they are the ones breaking my cycling. Last water change I added more beneficial bacteria to try and help the cycle.