Hey guys i have 3 corydora catfish i have had for a while now and i have never had any issues with them. today when i got home from work i went to feed them and i noticed one was sorta laying on it’s side and wouldn’t move so i tried to pick him up with the net (i honestly wasn’t sure if it was dead or not) and he didn’t really move and let me pick him up( usually a challenge and they run when i bring out the net) i placed him down and he started swimming in circles upside down then ended up landing on his back and didn’t move so i decided to move him into a bucket by himself just in case he is sick so he won’t hurt my other fish. both my other cories seem okay. i thought it might be swim bladder at first so i put in a few peas with him but he started twirling around in the bucket again and this time landed on his side. then i noticed a white spot on the side of him?? i don’t know what it could be?? is it swim bladder or is it something else? all my water primiters are great so it wouldn’t be the water that is the issue. i also just did a water change 2 days ago and this has never happened before and like i said both my other cories are perfectly fine swimming around like normal. i took a picture of the side of the sick one of anyone could tell me what is wrong please