I used to help care for them at the NY Aquarium. They were in a tank with flashlight fish in the Nautilus display. The tank was kept dark during the day with cool temperature and low flow. I used to feed them a lot of shrimp both live and frozen as well as a little frozen cubes. They need a lot of room and are very shy nocturnal creatures.
Hope that helps but I have a question for you. Why would you order animals and not understand their basic requirements. Please understand these are not fish for most of our aquariums.