ΔE 10.6, fair: the same colour family, but not a straight swap. Fern Green is more muted, cooler than Light Moss Green.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Fern Green is more muted, cooler than Light Moss Green.
The same difference applies the other way round: Light Moss Green is more saturated, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Light Moss Green on the colour wheel See Fern Green on the colour wheel
All matches: Light Moss Green equivalents · Fern Green equivalents