Essentially they are the Artemia of the fish world. Foods should be 0.5 to 1.5 times the mantle length of cuttlefish. Freshwater fish, fresh water amphipods and fresh water shrimp could be tried if live marine foods are not available. Artemia should only be tried as a last resort. Hatchlings grow very quickly and will eat a lot of food.
Most hatchling cephalopods double their weight every week or so for the first few months.
Food quality and quantity are very important at this point. If you have too many hatchlings it would be a good idea to farm some out to friends instead of starving all of them. Hatchlings can be reared as a group in a small tank, or in a floating container in your main tank. They will associate you with food and take food from tweezers, a skewer or your hand at a very young age. If all goes well, your cephalopods will quickly out grow their rearing containers and you can train them in international espionage and unleash them on the world.