I also wanted schooling fish, did allot of reading on it and this is what I found. In the ocean fish school for protection and in large numbers (which we can not do due to the size of our tanks), some fish will swim together but not really a school of fish. But I tried anyway, in 135gal tank I place 24 chromis, tank mates at that time was hippo tang, auriga butterfly and lawnmower blenny. Since later finding out the chromis were in the damsel family (should of done more reading about chromis) they picked each other off (in a years time) till one was left, which parishes in an ick out break (which is another story). The other types of fish that other have recommended will work better than chromis but in odd numbers and they will probably swim together at times, but not really as a school.