Who Gives A Fish Forums

i got this frag from my lfs about a month ago, it was a two-polyped acan and it was doing great, eating at night and all that. but over the last 2-3 days, it's started to recede and i can see white skeleton showing around the polyp. my tank's a 30g, i use coral pro salt mix, and i did a water change ...

I also have a pair of Green Chromis in my tank. One is slightly bigger than the other and it does chase the smaller one occasionally, but that's as far as it goes. No fin nipping or anything like that. I've also got an electric blue damsel that can be a bit aggressive towards some of the other fish ...