Berghias eat Aptaisias, and Aptaisias only. They might starve travelling from one to the next if they are too far apart.
We are trying to breed them, and it is difficult. To even have a slight chance to succeed, you need to actually breed Aptaisia aswell, they need tons and tons to survive and in all sizes from tiny to medium to large depending on their stage of life.
IMO, peppermints combined with Kalk, Joe's Juice, etc. (for the real large ones) works much better.