Bivalve ID

[AydenLincoln]

Okay so I’ve had this bubble coral for awhile and I always saw this bivalve but I assumed it was dead because it was always open and I dip all my corals. Well today for the first time I saw it move and realize it is very much alive and has been. What is it?

 

[AydenLincoln]

Now that more of the work is up…does anyone have an answer? Could you possibly identify this sponge too? It’s white with black dots. And yes I know there’s thousands of species of sponges but maybe someone has an idea? @ISpeakForTheSeas