Hatchling cuttles need small easy to catch food, and lots of it. Live mysis is currently the best food available, and yes it must be live. Many new cuttle keepers think they will be able to catch enough mysis for their cuttles from their sumps or from LFS tanks, but the amount available from those sources is nearly never enough. A hatchling cuttle will take a mysis at least 2 times a day, but 4-6 is preferable because the more nutrition that gets into the animal the faster it will grow. So, if you have 5 cuttles, and we average 4 mysis a day that comes out to 20 mysis a day, or 140 mysis a week, which is a lot of mysis. Given that mysis can be cannibalistic, keeping mysids in stock can be difficult, and getting a shipment weekly (reedmariculture.com or aquaculturestore.com) can be expensive. But it is necessary; cuttles need to eat. Brine shimp, adult or baby, has been tried as cuttle food many time, but is simply not sutible – the cuttles who are fed such a diet fail to thrive. After a month or so,amphipods can be introduced into the cuttle die, before that they may be too strong for the cuttles easily getting away from them, or even injuring them. These can be collected locally if possible or ordered from many online sources.
When the cuttles are between 6 -8 weeks, they can be weaned on to thawed frozen mysis. Start by introducing the thawed frozen food along with the live food, so the cuttles become accustomed to non living foods. The key here is to have enough flow in the cuttle’s aquarium to keep the non living foods moving around – generally if they stop moving they will be ignored.