What is this ?coral? It appeared on the live rock I bought

[Gore15]

I got some live rock and after a week I noticed this ?coral? Becoming alive on it. Any idea what is it?

[sr2z]

Looks like some species of encrusting sps coral, maybe a montipora?

[Clown79]

Looks like a monti plate. The bright green is the polyps

[Tired]

That's a montipora, yep. You should turn it so it's not touching the sand. That whole white area between all the green spots is also part of the coral. 

 

Was this live rock previously in someone else's tank? 

[Gore15]

7 hours ago, Tired said:

That's a montipora, yep. You should turn it so it's not touching the sand. That whole white area between all the green spots is also part of the coral. 

 

Was this live rock previously in someone else's tank? 

Yes. It was in their sump area. I bought about 3kg from him to put into my tank. Plenty of good things came out of that purchase. 
 

can I ask what will happen if coral touch the sand?

[sr2z]

32 minutes ago, Gore15 said:

can I ask what will happen if coral touch the sand?

Well, it won´t be doing well. It´s not that much about the sand itself, it´s more about the lighting the Montipora receives. They need light (a lot of it) and your Monti should be turned upwards. The part which touches (or is half buried, hard to tell) will die out because of no or minimum light.

[Tired]

No wonder it's bleached-looking, if it was in the sump. That area between all the polyps should have colors, too. 

 

It needs to be turned upward to face the lighting. There are also some anecdotal reports of SPS corals slowly receding if their tissue touches the sand too much, even if it's not buried.