Zoa skirts disappearing

So I'm not sure what's happening. This is the first coral I had in the tank and it has grown well. Recently it has started to do this. I'm not sure what's going on. The flow was not directed at it and the lighting is good. It's good enough for my small birds nest. Any ideas. I looked around and couldn't find a solution.

 

You have zoa eating nudibranchs.

And they will look like what they ate.

 

Have you added anything or changed anything lately. It could be nudis but I had this prob a while ago with only certain zoas. It turned out they didn't like one of the additives I was using. To play it safe you may want to dip them.

 

It's a small tank so I only add a little of seachem fuel every other week opposite water changes. I'll pull them out and dip them. I've dipped everything in that tank though. Well maybe not the LR. Going with dry rock in my new 40 to hopefully avoid this.

 

What did you dip them with?

 

I use revive and follow the bottles directions.

 

IMO- check your tank a couple hours after lights out.

 

Ok. I'll be up late tonight setting up my 40B so I'll take a look. Should I use just moonlights or all lights off?

 

Moonlights or if your have a little red or blue led handheld light.

 

Sounds good.