Koi Fishes Diving Near Coral reefs

Koi Fishes Diving Near Coral reefs , koi were commonly believed to have been bred from the common carp (Cyprinus carpio). Extensive hybridization between different populations, coupled with widespread translocations, have muddled the historical zoogeography of the common carp and its relatives. Traditionally, Amur carp (C. rubrofuscus) were considered a subspecies of the common carp, often under the scientific name C. carpio haematopterus. However, they differ in meristics from the common carp of Europe and Western Asia, leading recent authorities to recognize them as a separate species, C. rubrofuscus .

Although one study of mitochondrial DNA (mtDNA) in koi was unable to find a clear genetic structure matching the geographic populations (possibly because of translocation of carp from separate regions), others based on mtDNA, microsatellite DNA and genomic DNA found a clear separation between the European/West Asian population and the East Asian population, with koi belonging in the latter.

Some coral species, such as brain coral, are hermaphrodites, which means they produce eggs and sperm at the same time. Sexual reproduction occurs during a mass coral spawning event that, for some species, happens only once a year.

Other species, such as elkhorn coral, are gonochoric, which means they create colonies composed of either all males or all females. Within each coral colony all the polyps will produce only eggs or only sperm. For successful reproduction, the colony must rely on a neighboring colony that produces the other reproductive cell.