I want to call that a mirror instead of a muddler . nice ones
Now I don't know what a "muddler" is, but I've been breeding koi for over 30 years and that fish would be called an "armor scaled" carp by koi enthusiasts. My guess they mean the same thing. I posted this in the past....
"Mirror carp" are a type of "doitsugoi" (Japanese for German carp) that is a genetically derived condition following simple Mendelian inheritance.
Mirror carp generally have a double row of scales down the back, a row of large scales along the lateral line, and maybe a few other scales scattered about the fish, but more than 50% scaleless.
The other types include "Leather" (no or almost no scales at all), and "Armor" (completely covered in very large mirror scales.)*
The pattern can arrive spontaneously from normal scaled carp, but usually is associated with other doitsugoi in the bloodline.
Eg. Mirror x mirror yields 1/4 normal scaled, 1/4 leather carp and 1/2 mirror carp in the offspring.
* This fish is a special case where the armor scales are much smaller than usual, still I believe, an armor scaled carp. Very interesting fish and an excellent catch.