They are very hardy and they grow fast. I had one bleached completely when poisoned by copper and it is now a beautiful colony with lots of nice shade of pink, purple and blue. Amazing how fast they grow.
As long as there is good polyp extension the coral is happy. If you want it to grow better and have good color, zeovit amino acid and coral vitalizer each day will help feed it well.
When I got it in february, all brown and ugly (from Fragalot):
copper poisoning (Kent carbon). I thought it was dead for sure, but kept it in the tank just in case:
and now, still a bit bleached from underneat but recovering nicely..they are really tough:
Some of mine also have some white tips when growing, especialy the green with purple polyps on the right have white tips when it is growing.