What is this green thing?

[Clutchiee]

Small green thing on the clam.

Also how should I get rid of the aptasia on the side? Scrape? Pluck? Both?

 

[Clutchiee]

Under whites

 

[EeyoreIsMySpiritAnimal]

Looks like a majano anemones.

 

[Clutchiee]

Looks like a majano anemones.

Yes, it seems like it was. I exterminated it (hopefully) along with an aptasia and an asterina starfish.