Snowflakes are great fish. I kept one for several months in a FO tank so I'll share what I know;
Feed a varied diet, to include krill, chopped shrimp, squid (mine loved squid), clam, silversides or other meaty foods. They don't need to eat every day and 3 times a week will suffice. Their eyesight is poor so they locate food by smell. You can use a feeding stick to target feed, or drop it in the vicinity of their burrow and they'll find it, providing it does not get picked up by a faster fish with good eyes. They will spend most of their time hiding under rocks with just the head poking out. They can dig ferociously in the substrate to get underneath something, and will do so even when they have established a favorite spot. If you have a dsb, be prepared for the occassional "snowstorm". They are known escape artists so make sure the tank is well sealed. They are quite hardy, disease resistant and relatively peaceful with most fish, but they will go after some crabs and shrimps. i kept mine with a few good sized hermits and he never paid them any attention. He was also routinely serviced by my two cleaner shrimp who would even clean the inside of it's mouth. In a reef setting, the concern would be the fact that eels lack the social graces of many other fish, and kind of blunder around the tank, in and around rockwork, posing the threat of knocking corals and such off their perches. They can and do get feisty at feeding time and go into sort of a coiled up feeding frenzy. it's at this time when they are most apt to latch onto something that gets in their way and they might mistake for food. As far as growth rate; I got mine when he was about 7 inches long. He was a little over 18 inches 1 1/2 yrs later and still growing. Very powerful fish. Good luck and hope this helped somewhat.