Outdoor ponds often feature koi, a large ornamental carp. Selective breeding has produce many of varieties of koi, delineated by both coloration and fin shape. Between the number of varieties and their usually Japanese names, selecting a koi can get confusing. However, the characteristics of a yamabuki koi with standard fins are relatively straightforward.
The koi (Cyprinus carpio) is a larger relative of the goldfish. Ornamental ponds in Japan have featured selectively bred koi for centuries. Koi can thrive in temperate and subtropical climates, making them ideal for outdoor ponds in much of North America, Europe and Asia. Almost all koi are the same species, though some varieties were created through hybridization with closely related species of carp. Dozens of varieties and sub-varieties of koi exist, delineated by their coloration and finnage.
The yamabuki koi are a subtype of the ohgon koi. In Japanese, "ohgon" means "gold." This refers to the metallic, reflective scales seen in these koi. The ohgon group contains a number of other types of koi in addition to the yamabuki, including the regular ohgon and the gin. The "regular" oghon has a gold coloration coupled with reflective scales, while the oghon gin has a metallic platinum or silvery color.
The word "yamabuki" refers to the overall color of the fish. The word translates to "pale yellow" in English. Since they belong to the ohgon group, their coloration consists of a paler yellow than the regular ohgons, but with the same characteristic reflective scales. This gives them a metallic look, like other ohgon koi.
When a koi -- or any fish -- has "standard" fins, it means that their fins resemble the original, wildtype fins in terms of shape. This means the fins of a yamabuki koi will have the same shape of a wild-type koi, except in terms of color. This contrasts with butterfly koi, a variety of koi with long flowing fins. Butterfly koi have some popularity in the U.S., but connoisseurs, particularly in Japan, tend to view the standard-type fins more favorably. The fact that butterfly koi were created via hybridization may influence this way of thinking.