Back when JD's were first bred in captivity two regular jacks would have lets say 100 fry 5-15 were blue and they were culled. Someone over in Germany selectivly bred JD's for the Electric Blue coloration. The way it occured was two JD's with the recessive gene bred and a select few showed a blue color. Then a electric Blue was selected to bred with a regular JD. Much more Blue fish. If you breed a blue with a blue there will be no blue ofspring, so you have to breed Blue with regular. Also EBJD's Grow VERY SLOWLY more or less 1 inch a year, that means that they mature VERY SLOWLY also adding to the price. Due to the rarity of the blue some people who are looking for the easiy money inbreeding EBJD's making them smaller, grow smaller, look extremely ugly when fully grown, and ridiculously priced, at my lfs EBJD's cost $35 a piece. Some pictures of fully grown EBJD's that are circulating are extremely beautiful but they are even more prized.