Nonody knows what they eat and they generally don't take to supplemental feeding. It's generally thought that they feed on biofilms that form on hard surfaces. Besides having a large tank with lots of established LR there is no way to ensure they have enough food. For that reason and the fact that they ship poorly and are very sensitive to changes in salinity, they generally do poorly in the hobby. Most don't make it to the 2 year mark, so that's about the minimum time it takes before success can be claimed.