I just got myself what I think is a snow coral hatchling at Petco, and they had 7 hatchlings in a 10 gallon tank.
I seemed to get really lucky with mine because so far she eats like a champ and is incredibly active, but needless to say I made sure to check for respiratory / mite problems pretty thoroughly before buying mine.
Was really sad to see like 4 hatchlings under the same hide (which, incidentally, was one of those giant half log turtle hides... way too big for hatchlings).