the fish would greatly prefer larger numbers of their own species, rather than lots of species, but fewer numbers. they would also demonstrate more natural behaviour
edit: i misinterpreted ur post, yeah u probably could get away with ~60 fish and 5 species
as an example something like
10 flame tetra
10 black widow tetra
10 rummynose tetra
10 cardinal tetra
8 bronze corydoras
would be fine