I would try whatever frozen food you currently use. I was reading on starfish last night and thats what they said to try, any carnivore food might work. Just get it to one of his legs so he can find it. It was also suggested that you could put food down and move the starfish onto it. Not so sure thats a good idea but it was mentioned in the article I read
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.