They should have their own tank preferably. A net is okay for keeping most fish from eating them but ends up stunting their growth. In optimal circumstances the fry should have a separate tank with a filter and heater for themselves. They can be fed a multitude of foods, crushed flakes, daphnia, baby brine shrimp (frozen or you can hatch them yourself) to name a few. They should be fed a few times a day and have a 10% water change every day or every other day because of the very frequent water changes.