Clown Triggerfish!!!

[Siddique]

So I've had a pink tail that died on me recently, when I examined the body, I noticed that the head and stomach was a bit sunken in even though it was eating very well.
Now I have a Clown Trigger that is showing the same signs of sunken in body. I feed vigorously but I am not seeing any permanent weight gain or growth. What could be causing this? Cyanide poisoning maybe? Or a lack of it's natural diet?

 

[vanz]

probably worms, try prazipro...worked wonders on my sargassum