I've seen both cardinals and anthias make some nice looking schools in reef tanks.
I bought some frags off a guy that had a 90 gallon with a fair size group (10 or 12) chalk bass in his mixed reef tank and they actually looked really cool together. I'm not sure they are considered 'schooling' fish or 'shoaling' fish but they definately hung put together in a pretty tight little group and apparently they are not aggressive towards any of his corals.

Cheers,
PatD