I have just upgraded to a 56cm, 70l tank, which has 6 harlequin rasboras, 4 5banded barbs and 1 otocinclus. I want 5 or 6 salt and pepper catfish ( corys), and a shoal of tetras. If I kept a small shoal, I would want a larger pair of fish, I've kept dwarf gouramies before and loved them. Would I be too over stocked, and can anyone recommend me any fish for shoals or a pair?