I have a clown that has been in my tank for over 6 years I believe. Last night he was fine and this morning he was swimming very weird, sideways upside down and at times fine up and head down. Does not show any signs to bloat. No changes were made except I made an adjustment to my skimmer last night and it seemed fine. But this morning it was boiling over and I had a bio pellet reactor feeding into the skimmer. All other fish in the tank seem fine. I have him netted and and getting a QT going. Not sure what happened. I suspect swim bladder but I don't see any bloat. Other option from reading posts is maybe just backed up or he got some sort of a bacterial infection affecting his swim bladder. Once I get him in the QT I was planning on monitoring for a few days. If he continues to show no improvement thinking I need to treat for Bacterial infection. But not sure how long to wait before treating and don't want to wait to long. Also what would be options to use to treat something like this. Once in QT I can get a better video. The one I have right now may not show very well and not sure if I can post here.