Shusui are the doitsu (scaleless) version of Asagi. The blue reticulated net pattern seen in Asagi is replaced with icy-blue or sky-blue scaleless skin, and a single row of scales running down the dorsal line of the body. Similar to Asagi, the red (hi) appears on the gill plates, pectoral fins, belly and tail. Unlike Asagi, it is generally desirable for the hi to extend up above the lateral line and onto the back.
The most important aspect of the appearance of Shusui is the row of scales that run down the dorsal line. In the highest quality Shusui, the row of scales begins just behind the head and is formed by lines of two identical scales side by side, which split onto either side of the body at the front of the dorsal fin, then rejoin into a single line of scales at the back of the dorsal fin. Shusui may or may not have a secondary row of smaller scales along the lateral line.
"Mudagoke" refers to stray or extra scales on Shusui that appear outside of the row of scales down the back. These scales distract from the uniformity of Shusui and generally create an inferior koi.
Similar to Asagi, the hi is an orange-red or rust-colored red that is darker and more subtle than the bright, vibrant hi generally found in Kohaku, Sanke and Showa. The hi should compliment the row of scales down the back, and should appear on the gill plates and shoulders, but not on the head. Some Shusui exhibit a desirable trait known as "motoguro", patches of hi that begin at the base of the pectoral fins and spread outward over part of each pectoral fin.
Shusui differ from Asagi in regards to hi above the lateral line. While hi above the lateral line is always considered a fault in Asagi, it is generally desirable in Shusui. Some sub-varieties of Shusui are determined by the placement of the hi above the lateral line. This is discussed in further detail in the table below.
The highest quality quality Shusui have a bluish-gray colored head that is clear and free of any blemishes or marks. However, a truly perfect Shusui head is very rare. The skull will almost always be visible through the head of young Shusui (10" or less in length). When examining young Shusui, look at the nose area. If the nose area is clean and blemish free, then the rest of the head will generally clear up with age, and the visible skull will disappear from view.
For more Shusui images, check out the Shusui Image Gallery and Butterfly Shusui Image Gallery.