We have two humpback and they were from Aquatica Montreal, about 2.5 inches each. We tried Krill, silversides etc.. but after 3 weeks of not eating (the store could not get then to eat either) they were pretty lean. Eventually we got desperate and added some mobile feeder fish, that got them going... although one of our daughter's recanted "Goldfish, the snack that smiles back !". They will eat mysis, shrimp whatever now... and they left their other buddies alone so they moved on to their own tank that probably six months ago now.