If it’s from whirling syndrome then prazipro will treat it. It’s from a protozoa. Just from seeing the fish in the video. It’s hard to make much out at all.
I think it is protozoa too, if disease related, hence suggesting either metro/hexshield, gut delivered magnesium sulfate or/and flubendazole. They all have affect against various protozoa.
I am not aware of prazi having any effect on protozoan infections. It is effective against parasitic flat worms mostly from what I know but it does have some effect against some external parasites such as trichodina which are normally non-pathogenic but can become so.
And its possible not to be a disease, as already mentioned, but some sort of internal blockage, etc..The fish is living and eating so it doesn't seem life threatening but if it can be helped, its no harm. I can see the poor thing wants to live
There is also General Cure.
Hope I don't get blasted for bringing that up.
Really thinking this is a bladder problem though. It may be tough to beat this problem.
API General Cure is an option I suppose, being a combo of prazi and metro.
I think the OP has some info to ponder about and decide what they'd like to do. I think we're all doing our best to guess what it might be..
Good luck.