What's on my zoa?

[Shadowman7]

Hi,
Had a little zoa colony for about 2 months as happy as can be, the last week they've closed up in the last week and haven't opened since.
All paras are good and my mushroom and frogspawn are fine.

I have 2 theories:
1) whatever the thing is in the attached picture is causing bother, potential nudibranch?
2) there is some aptasia on the rock they were placed on, but I moved after I noticed ~ 4days and haven't opened up. Similar position in tank just a different rock
Or anything else you can think of?

Thank you

 

[vetteguy53081]

Hi,
Had a little zoa colony for about 2 months as happy as can be, the last week they've closed up in the last week and haven't opened since.
All paras are good and my mushroom and frogspawn are fine.

I have 2 theories:
1) whatever the thing is in the attached picture is causing bother, potential nudibranch?
2) there is some aptasia on the rock they were placed on, but I moved after I noticed ~ 4days and haven't opened up. Similar position in tank just a different rock
Or anything else you can think of?

Thank you

Appears to be a slug or nudibranch
Siphon or remove with tweezers and discard

 

[Shadowman7]

Appears to be a slug or nudibranch
Siphon or remove with tweezers and discard

Thank you,
How difficult should it be to remove, given it a good pull but it's not come off?