Tiger Barb problem

[Yenko]

There's a thin, white thing trailing from one of my tiger barbs, just behind the anal fin. He looks pretty bloated as well. He's acting normally, but I'm worried this is part of his intestine; my fish have gotten a fairly high-protein diet lately. Can anyone tell me what this is, if it can be treated and is it contagious?

 

[scott1000]

maybe it's poop?

 

[Yenko]

It's white, though. It's normally brown. It also had translucent sections, which, to me, look like intestine.