I have a blue phantom plec with tetras and cory cats in a 20 gal and all was well this morning but added a small pad of acurel ammonia reducing pad to filter and fed fish and now after maybe 3 hours after adding pad and 30 mins after feeding everything is breathing heavy includeing the plec and the plec also fans self withfins every few mins wat could be going on and wat should I do added some neutral regulator and stress zyme to hopefully counter part of prob