sudden failure?!

[blackcap]

I recently bought a Racoon Butterfly fish. I had just done a major water change and cleaned up most of the green algae I had. I have one bubble tip anemone, several feather dusters & mushrooms, 1 or 2 crabs, a small green chromis, a medium blue damsel and 1 large tomato clownfish. Everyone seemed to be getting along, though a few months ago my green chromis and blackcap had been attacked by something. The blackcap has dissappered since then. One of my crabs disappered after the water change. Everything else seemed fine though. My water has always tested well and I've had few problems.
Well this Butterfly seemed to fit in, he puffed up at the clown a bit but everything was good. Then he started getting a white or pale patch all over one side of him. Then his eye became clouded and then his other side developed a white patch. He started pecking at rocks as if looking for food instead of eating my flakes. Then he started swerving into rocks like he couldn't see. Unfourntately he died before I was able to get him out of the tank.
My dealer says it sounds like stress. Is it possible that's all it was? I'm getting rid of my clown because he is harrassing my damsel who is now turning quite pale. My green chromis is missing now too. I'm also going to get my water tested and wait to see how my damsel and anemone do. The anemone has shrunk on me and won't open up. The mushrooms went into hiding when I introduced the Butterfly.
Thanks for any suggestions!

 

[beth]

Butterfly fish are specialized feeds, and not likely to do well on flaked foods. Sounds like he may have developed a bacterial infection.
Can you give some more info about your tank, age, size, what's in it, etc?