Personaly i would not say excactly how many fish to put in a school, purely due to the fact that as soon as there are two fish, is that not a school ? Or is it a pair ? Also we as aquarists do we actually have a tank big enough to hold a school of fish ? Or does that depend on the family or species of fish ? Yea i know more questions than answers

But think about it, as some fish school in their thousands, while others are happy in Small groups, personly i think it is best to try to find out as much as you can about, the scooling behaviour of any fish you are thinking of keeping, prior to purchessing them. Saying that i personaly think that a group of a minimum of 6 is a good idea for schooling fish. To feed them i would say what you are allready feeding should surfice, but if you want you could aso try feeding tropical flakes and daphinia