ΔE 19.0, loose: different enough that you should pick on purpose. Fern Green is a little darker, warmer than Dragon Blue.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Fern Green is a little darker, warmer than Dragon Blue.
The same difference applies the other way round: Dragon Blue is a little lighter, cooler.
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 Dragon Blue on the colour wheel See Fern Green on the colour wheel
All matches: Dragon Blue equivalents · Fern Green equivalents