The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
I got a sun coral from the local fish store and it's difficult to get it to open. Should I entice it with some phytoplankton? Or what else should I do?
Yes, but get it eating first. Then when it's in the habit of eating, introduce food to the water column when the lights are on. Then feed them.
Usually, they will start to open during daylight hours after some weeks of day time feedings.