The famous Berlin cross of the swordtail is the result of a gene transfer by hybridisation. Sounds complicated? The Berlin Swordtail is a breed originally produced by crossbreeding species, which was later adapted to the appearance of swordtails by displacement breeding. In red and yellow Platy (Xiphophorus maculatus) strains, black-spotted animals occasionally appear as a result of spontaneous mutation. This color mutation is sex-linked and occurs only in female Platys. By crossing such black-spotted Platy females with red males of the swordtail one obtains hybrids, with which also the males can carry the black spot. These hybrids are, like all known crosses of different Xiphophorus species, intermediate between the parent species. I.e., they have gotten something from both parents regarding the appearance. The hybrid males are larger than normal Platys, but as high backed and stocky as these. The sword of the hellerii-father is hardly recognizable. Only by consequent crossing of the black spotted hybrid males to red female swordtails one finally got Berlin swordtails.
We almost always have Berlin swordtails in stock, as this pretty, very varied spotted breed has enjoyed great popularity since 1916, although breeding them is not easy and requires a great deal of knowledge of genetics. We obtain our Berliners from various breeders in South and South-East Asia, sometimes also from Europe or Israel.
For our customers: the animals have code 420913 on our stocklist. Please note that we exclusively supply the wholesale trade.
Text & photos: Frank Schäfer
