Sick Frogspawn?

[mariaharris224]

Hey! I'm pretty new to reefing and could use some help diagnosing what's going on with my frogspawn. So I noticed about a week ago that my frogspawn's mouth was pretty wide. At this time all the other coral in my tank, including another frogspawn all looked happy, so I tried not to worry about it. I left the tank alone for 2 days and in that time a fish died (new and already sick addition from Petco, I know bad choice). Today I got back and while the frogspawn looked nice and fluffy the mouth was even larger, and I noticed when it began to retract for the night that I could see some skeleton on a head. I don't know if I'm being paranoid, but is there anything wrong/ anything I should do? Id appreciate any help :/
*My parameters were all perfect pre-dead fish but I'm going to have to get them retested.

pics from Sunday and Today (beginning to retract because of night)

 

[Shirak]

Rock looks pretty bare. How long have you had it? What are your nutrient levels? Nitrate and phosphate. Do you target feed them at all? I find mine do better with a little target feeding a couple times a week.