Hybrids are not new, it is even suggested for aquaculture to cross them for better fitness against Herpes Infections:
Hedrick, Waltzeck, McDowell, "Susceptibility of Koi-Carp, Common-Carp, Goldfish X Common-Carp-Hybrids to Cyprinid Herpes Virus-2 and Herpesvirus-3", Journal of Aquatic Animal Health, 18: 26-34, 2006
They can be differentiated by genetical and/or morphological analysis:
Pullian S. and Smith P.J., "Identification of Hybrids between Koi (Cyprinus carpio) and Goldfish (Carassius auratus)", New Zealand Journal of Marine and Freshwater Research, 1987, Vol. 21: 41-46
Smith P.J. and Veagh S.M., "Genetic Analysis of Carp, Goldfish and Carp-Goldfish-Hybrids in New Zealand", DOC Research and Development Series 29, New Zealand Department of Conservation, 2005
Hedrick, Waltzeck, McDowell, "Susceptibility of Koi-Carp, Common-Carp, Goldfish X Common-Carp-Hybrids to Cyprinid Herpes Virus-2 and Herpesvirus-3", Journal of Aquatic Animal Health, 18: 26-34, 2006
They can be differentiated by genetical and/or morphological analysis:
Pullian S. and Smith P.J., "Identification of Hybrids between Koi (Cyprinus carpio) and Goldfish (Carassius auratus)", New Zealand Journal of Marine and Freshwater Research, 1987, Vol. 21: 41-46
Smith P.J. and Veagh S.M., "Genetic Analysis of Carp, Goldfish and Carp-Goldfish-Hybrids in New Zealand", DOC Research and Development Series 29, New Zealand Department of Conservation, 2005
