Mix some All Bran or Weetabix with some used aquarium water in a small container (a buttercontainer will do) to for a paste.
Let it settle for a few minutes & then add a spoonfull from a Bananaworm culture.
Wait for a day or two & you can start harvesting them the mix you have.
I suggest that you do 2/3 mixtures, so you'll have plents of Bananaworms to feed.
Please treat Corydoras as community inhabitants & not as scavengers.

