Shiro Muji

Shiro Muji are a product of Kohaku spawn, where the red pattern is completely absent.  Generally, Shiro Muji are culled out of the Kohaku spawn at the first culling.  However, an occasional Shiro Muji with a clear head and great skin quality will be kept to raise further.  Gin Rin Shiro Muji (such as the one pictured above) are also occasionally kept to grow out further.
What To Look For
Since Shiro Muji have no pattern, it is highly important that the scalation and color of the body be near perfect, with very little or no blemishes or flaws.  The head of Shiro Muji is equally important.  It should also be smooth and consistent, with no blemishes.