tangs or triggers do not stay small. if you feed them they grow. if you dont they die. its very difficult to have schools of fish in a salt tank. you are thinking something like a school of freshwater tetras. you dont get that unless you have a tank in the of thousands of gallons. marine fish dont work that way. you can put small schools in there but the dominate fish or pair in the school will torture the others to death. i would recomend that you look at getting 1 fish of each of 5 or 6 individual species that would get along. ie. a pajama cardinal, a blennie, a pygmy angel, a wrasse,. etc. have lots of hidy holes and dont try to crowd too many in there. you could have a very nice display and there are lots really nice colourful small fish that dont do well with another of their own kind. just be careful what you buy and do a bit of research so the fish you buy are compatable.