Corys were on of the first fish I ever introduced into my tanks, and they seemed to do well. To be honest, as long as your water quality is good, and you keep the substrate clean you should be fine.
However, you must make sure you have variety in their diet. I feed all my Corys a mixture of bloodworm, white mosquito larvae, tablet food, flake, and occasionally a small amount of veg (such as cucumber.)