Three weeks ago,I purchased a piece of live rock that looked like a dead moon coral. Last night I noticed slight green colors around rims of poylps, like crustation. Could this coral still have life ?
It is definitely possible that there could be some live polyps on there, though it's more likely that it's algae or a sponge of some sort. If you can get pics that would help, but just keep an eye on it and as time goes on it will be easier to ID.