What are these small organisms? Found only in very hidden places and not reproducing fast or growing large either.

[Goaway]

It could be a variety of sponges. But it's an encrusting white sponge, from all i can see. Doesn't appear to be finger/spagetti sponge.

 

[Sushiboy225]

It could be a variety of sponges. But it's an encrusting white sponge, from all i can see. Doesn't appear to be finger/spagetti sponge.

Thank you, the only reason I ask is because it appears to have the same white stalks and balls as the Christmas tree hydroids linked.

could hydroids be growing through the sponge?

 

[elysics]

Looks to me like the reproductive phase of some sponges. Tethya gracilis' reproduction mode looks very similar, though Tethya are ball sponges, there's probably encrusting ones with a similar mode of reproduction though

 

[Sushiboy225]

Looks to me like the reproductive phase of some sponges. Tethya gracilis' reproduction mode looks very similar, though Tethya are ball sponges, there's probably encrusting ones with a similar mode of reproduction though

Wow, that definitely looks like it could be that too! What would be the best method of documentation to get an accurate ID? Would cutting some off and putting it under a microscope be best?