Small Corydoras Species Sought & Corydoras panda

I'm looking for about 20 1-2 month old Corydoras.

Preferably something which doesn't grow too big & schools well.

I've got Corydoras panda & dont mind increasing the number but then again variety's always good & something thats easy to raise would be great.

The C panda have spawned when I had them seperated out but only produced 4 - 6 eggs at a time (not sure which female was laying), I lost most to fungus & didn't manage to raise the fry.

Feeding was attempted with fry powder & microworms.

They were spawned in a bare tank with a little plant but became xtra spooky.

The Cory's are seldom seen (I have 12) in the main system being extremely shy.

Main tank: 4 foot x 2 foot x 2 foot roughly. Heavily planted with lots of wood.

Panda territory: behind / under the logs.

I figured that increasing the number would help get them out & about more but not with 12 (small pandas do thier own thing & dont hang with adults in this system).