They key to remember is that eeach type of COry is a different species. They're not just the same fish in different colours and patterns.
Once you get that it's a breeze. They have slightly differnet temperaments, and as far as care goes, as already mentioned, their needs differ slightly. Generally this just means that making sure you find a temperature that is suitable for all the species you keep. I have Sterbai and Paleatus in the same tank. One likes higher temperatures, one likes lower, but there is a suitable overlap. As with most fish they are generally adaptable with ph and water hardness as long as you avoid extremes (though mine are fine in very hard water).
Mine get peas occasionally. Like jollysue said, a sinking food and bloodworm will see them fine.