Hitchhiker coral ID
 

Can anyone tell me what this is? Came attached to rock for a colt coral that was purchased some time ago.

for some reason I want to say thats a young plate coral

Plate for sure.

That is a wicked hitchhiker!

hitch hiker
 

had an exact same hitchkiker. in due time you'll find this baby plate coral detach from rock and become free living.

Thanks for the feedback. Any special requirements for it? Preference for high or low light etc?

It actually expands quite a bit at times, then shrinks when there's something nearby (i.e. snail, shrimp)

If you look to the top right corner in the background, that looks like a dead plate coral too.

You don't really need to do anything at this point. You could feed it a pellet or some brine shrimp once a week. It is a very slow eater so make sure nothing steals the food from it.