Vishuls have currently one non-hereditary mutation that will not pass directly to offspring in breedings. However the way one can get a Vishul with Sunglow is pure luck as it is very rare and will only occur randomly in breedings as the non-hereditary mutations in real life do.
Non-hereditary mutations are not optional to show meaning if your Vishul happens to have a mutation, it is required to be present on the design.

Sunglow

→ This mutation covers the Vishul completely with white/off-white color.
→ Sunglow covers almost every marking available in-game except Spotting, Sewed, Ripple, Masking and Suntan. These markings may appear on top of Sunglow but are completely optional. Additionally if any of these markings are present, their colors should be picked from the provided swatch.
→ Sunglow must have at least a dark dorsal stripe present of which color should be picked from the darker end of the provided swatch.
→ It is optional to show soft streaks throughout the design. These streaks' colors should be picked from the provided swatch and their edges should be moderately soft or even gradient in appearance.
→ If there are streaks present, they should not cover more than 40% of the design.

SUNGLOW SWATCH:




EXAMPLES OF SUNGLOW: