Butterfly fish

[Cb24]

I recently bought an Auriga butterfly fish and he was doing fine swimming around and everything for two days and then now on the third he is swimming around and then laying on the ground. I know obvs this isn't good but does anyone now why this is happening?

There is no marks on him or anything
Parameters are fine
All other fish are fine
No fish that would bully him

 

[Cb24]

Anybody? I wanna do my best to make sure he is ok or if I can do anything

 

[TheTodd]

What are your parameters? What have you been feeding? How long had this tank been established?

 

[Bectan01]

+1 to all of the above. Post numbers. More info about the tank, tank mates? So we can help you find the answer...