For hardware description language file, see VHDL. VHD (Virtual Hard Disk) is a file format which represents a virtual hard disk drive (HDD). It may contain what is found on a physical HDD, such as disk partitions and a file system, which in turn can contain files and folders. It is typically used as the hard disk of a virtual machine.
Typically, koi eggs will hatch in less than a week. Koi eggs are very small, bead-like specks that can vary from milky white to yellow or green. Upon closer inspection, you can see two black dots through the transparent membrane of the egg. These are the developing eyes of the koi.
Breeding Koi. If you are interested in breeding koi, you need to have the koi larger than 25cm or else it is biologically impossible because the ovaries and testes in the male and female have not fully developed making them sexually imature. Anywhere after 25cm in length you can start to breed the koi fish.reeding Koi. If you are interested in breeding koi, you need to have the koi larger than 25cm or else it is biologically impossible because the ovaries and testes in the male and female have not fully developed making them sexually imature. Anywhere after 25cm in length you can start to breed the koi fish.