Longnose Butterfly Help

[Georgephoenix]

I have had my Longnose Buttetfly for over a month now and he's been eating fine and no problems with the other fish. He has had a bit of ich but was treated and he recovered well. However today when I looked at the tank I saw that he was just swimming in one place and looking downwards. I tested the water and that is fine, and no other fish have any illnesses. I noticed that lower fin looks quite fat and round and wondered if this had anything to do with it ?
Thanks in advance
George

 

[pinnatus]

Hard to see in that picture, but it doesn't look right to me. Please try to put up a better picture.

 

[Georgephoenix]

Hi thanks for your reply, unfortunately I lost him, turns out it was intestinal parasites.