Hi sick Loach I think?

[Loachie]

I have Clown Loaches 4ft tank, and two cat fishes and 2 silver sharks quite small still.

One of my clown loaches looks very skinny, he is still eating and every now and then goes for a swim around but lies down most of the time (I know they do this as odd behaviour) but, my tropical place where I got him from says my other clown loach was bullying mostlikely, but, then I read on another loach website they can get Skinny disease (knifeback) he seems to fit the symptons any other sujestions?

[Diana]

This does sound like Skinny disease. This seems to be a combination of issues, often internal parasites and a bacterial infection. Have a look at the stickies here at Loaches.