I would invest in a test kit, water chemistry is very important in reef tanks and can reveal a great amount of information if something goes wrong. I suspect that things aren't terrible since the green star polyps are open in the background of the picture, but the lighting may not be adequate as well. The fluval strip lights aren't exactly up to the task of growing corals despite their packaging claiming they are.
If you just got this acan, then it may also be adjusting to your tank. It can sometimes take a few days before they start looking like they did at the store.