Found on zoas

[mshonk]

So I noticed my zoas closing up. Not all just three small frags. Upon inspection I found these tiny whitish spots. They move similar to a hermit crab where the shell seems to swing around. I would say they are about 1/32" -1/16". I even got a shot with a macro lens for my phone. Not sure what it is any idea. I crushed one and I am pretty sure it has a shell.

 

[DSC reef]

Possibly collonista snails

 

[mshonk]

Possibly collonista snails

I would say these are more football shaped. I found another thread and it suggests ostracods. I think it may be right.