I would be sure they are either eating frozen (doubtful) & if they are not, be sure you are ready to care for them with live food!
Either Mysis shrimp (live) which are expensive, or enriched adult brine. They also love amphipods, if you have a healthy tank up, they will decimate your population quickly, so just be aware of that. If you don't have a refugium, be forewarned you are going to have a hard time feeding them by natural means! (they eat allot faster than they can reproduce!)
If you have any questions, feel free to ask!