My Gae...

[chibi]

I have a golden algae eater. He's little... about 3 inches. Anyway, I've been looking at him lately and noticed he's gotten extremely thin (I can see his spine-like bone going down the middle of his sides). He just sits on my plant leaves. On one side, I can see black things under his skin. It looks like poo. The thing is, it's all along where his organs are. It's strange. He's not changing color; I know they are known to change colors but it's not like that. No injuries. He gets along well with all my other fish. I've had him for about 6 months. Can anyone help?

 

[WILDER]

Usually when plecs go thin its internal parasites, he's not going to the toilet by the sounds of it.
Is the anus red and inflamed
Also going thin and deformaties can be fish tb.
I would issoalte the sick plec.