One of my rays stopped eating and is acting lathargic. I noticed it last night and changed the water. I even added the used FX5 I bought a little while ago. Nonetheless, I have not noticed a change in behavior. Just rests in one spot but and is not even responsive to food while the others are ravenous as normal. could the tank mates have stressed him out? He is the smallest in the tank but has seemed to hold his own up til now.

