SHOALING not schooling -
Shoaling: where fish congregate in an area and genrally swim together - traditional of marine fish and larger fish post fry,
Schooling: Where fish swim and attempt to clone each others manuvers, similar to tetras and danios.
Question posed again, Flagfish - Clown Knifes - Arrowana - Arapaima Gigas, whats a healthy Shoaling Number....