How Many

Even if you get a 125 your going to have probs. If those convicts make pairs the oscars will get a beating. Also if the oscars grow to fast the convicts will be lunch. I would get rid of either the oscars or convicts.
 
ChilDawg: thanks for posting some common names for those cichlids.

As for schooling/shoaling fish to add to a tank with some of these smaller cichlids, my first bets would be neons and rummynose tetras, as their schooling behavior is so pronounced when under a minor threat. I am also partial to Garnet tetras, Red Phantom and Black Phantom (note: not the same as Black Skirt) tetras, Emperor tetras (not good schooling fish, but interesting nonetheless), and Green-Eyed and Harlequin Rasboras.
 
No problem, Harry.

Ooh--I like Harlequin Rasboras--those would be tons of fun in that tank...if I had room for and time to manage (and transport to and from school) a planted tank, I'd go for a school of those or maybe Cardinal Tetras (but those are mostly wild-caught so they are less hardy than the other choices).
 
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