Classification of Nishikigoi
A number of Filipinos koi enthusiast didn't realize that koi japanese I mean japanese koi was just the same fish that was called locally carpa, the distinction is that karpa is the dialect for carp. I do believe that our ancestors have been keeping this fish a long time ago, I just don't have the evidence yet for now. I will do some investigation on this.
A number of Filipino koi enthusiast also have koi video uploaded to youtube already.
There are now local breeders who breed and sale koi sale.
The koi forsale prices varied depending on the location it was bought, you can bought cheaper prizes on hobyiest backyard breeds, but you need to emprove their quality by re breeding it, since these guys lack the technical know how in koi breeding.
I think koi forsale in Cebu are cheaper and also koi forsale in Dumaguete.
You can find online koi forums and website for those local keepers, hobbyiest and breeders for informations.
From Wikipedia, the free encyclopedia
This article is about the ornamental fish. For other uses, see Koi (disambiguation).
Koi (鯉?, English //, Japanese: [koꜜi]) or more specifically nishikigoi (錦鯉?, [niɕi̥kiꜜɡo.i], literally "brocaded carp"), are ornamental varieties of domesticatedcommon carp (Cyprinus carpio) that are kept for decorative purposes in outdoor koi ponds or water gardens.
Koi varieties are distinguished by coloration, patterning, and scalation. Some of the major colors are white, black, red, yellow, blue, and cream. The most popular category of koi is the Gosanke, which is made up of the Kohaku, Taisho Sanshoku, and Showa Sanshoku varieties.
Cyprinus carpio or the common carp is a species of fish from the family Cyprinidae. The origins of the common carp trace to the Caspian Sea, where the fish naturally migrated to the Black and Aral Seas, east to eastern mainland Asia and west as far as the Danube River. Within the same family, the Prussian carp (Carassius gibelio) were first bred for color mutations in China more than a thousand years ago, where selective breeding of led to the development of thegoldfish. The first known selective breeding resulting in ornamental fish. 
The common carp was known to have been aquacultured in Europe by the Roman Empire, which could have spanned a time period of 27 BC to 400 AD. Thecommon carp was also aquacultured as a food fish at least as far back as the fifth century in China. Common carp were first bred for color in Japan in the 1820s, initially in the town of Ojiya in the Niigata prefecture on the northeastern coast of Honshu island. By the 20th century, a number of color patterns had been established, most notably the red-and-white Kohaku. The outside world was not aware of the development of color variations in koi until 1914, when the Niigata koi were exhibited in the annual exposition in Tokyo. At that point, interest in koi exploded throughout Japan. The hobby of keeping koi eventually spread worldwide. They are now commonly sold in most pet stores, with higher-quality fish available from specialist dealers.
Extensive hybridization between different populations has muddled the historical zoogeography of the common carp. However, scientific consensus is that there are at least two subspecies of the common carp, one from Western Eurasia (Cyprinus carpio carpio) and another from East Asia (Cyprinus carpio haematopterus). One recent study on the mitochondrial DNA of various common carp indicate that koi are of the East Asian subspecies. However, another recent study on the mitochondrial DNA of koi have found that koi are descended from multiple lineages of common carp from both Western Eurasian and East Asian varieties. This could be the result of koi being bred from a mix of East Asian and Western Eurasian carp varieties, or being bred exclusively from East Asian varieties and being subsequently hybridized with Western Eurasian varieties (the butterfly koi is one known product of such a cross). Which is true has not been resolved