Chromis what is wrong with him?

[Lenareef]

Hi,
So i have this guy for month (+some days), he cycled my tank.. Doing ok, eating, swimming.. After 2weeks he slowed down.. And this is how he is now.. (video).. Put him in a diffrent tank.. After 2weeks still the same.. I guess he is eating.. He looks fine.. But just flowting there..
Any idea?
Thank you/Hvala

 

[monkeyCmonkeyDo]

You have flow pumps?
Anything for oxygen?
D

 

[Lenareef]

You have flow pumps?
Anything for oxygen?
D

Yes i have a flow pump.. But nothing for oxygen.. But in the first tank, where he got wird, he was with 5other fish, and all were fine, still are..