Is this killing my zoa's?

[Awkward]

Need an ID on this please. I have one colony of zoa's that all of the sudden aren't doing well. Everything else in the tank is doing amazing, including a different colony of zoa's that are a different color. The polyps that are dying off are forming a black goop around the shaft of each polyp, almost like a collar underneath the head. I just did a Coral Rx dip for them and I found a few of these little guys that came off in the water. It is really flat and almost paper thin. Not sure what it is or if it's even bad. These zoa's just have me paranoid now. Thanks everyone!

 

[fletch999]

looks like an isopod to me, I don't think they eat zoas, but some can be bad.

 

[Sugar Magnolia]

That's a harmless sphaeromatid isopod.

 

[Awkward]

Is this killing my zoa's?

looks like an isopod to me, I don't think they eat zoas, but some can be bad.

That's a harmless sphaeromatid isopod.

Awesome. Thank you guys! I couldn't find a match on the sites I was looking at. Any idea about the black slime ring on them? Here is a pic if it helps.

Its the polyp on the left. I hope the pic is good enough...