Tiny flower-like brown coral

[sailforfun15]

When I first put the rock in the tank, these were not visible, but showed up the next day. Today I didn't see them at all. What are they? Do they completely retract at times, or might my limpet have eaten them?

 

Is there a good place to go to begin to learn how to identify coral? I'd like to read a discussion of the main types, but also see a visual identification guide with thumbnails to help zero in on the right ID.

[birdman204]

looks like a GSP or Briarium frag. Usually it grows rather well even under PC lighting.

[sailforfun15]

I think these are daisy polyps. Unfortunately, since the day after I took this picture I've not seen them. I think my limpet may have eaten them.

 

Todd

[MarLooney]

i think birdman is right.