ΔE 15.7, loose: different enough that you should pick on purpose. Stegadon Scale Green is noticeably darker, more muted than Hydra Turquoise.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Stegadon Scale Green is noticeably darker, more muted than Hydra Turquoise.
The same difference applies the other way round: Hydra Turquoise is noticeably lighter, more saturated.
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 Hydra Turquoise on the colour wheel See Stegadon Scale Green on the colour wheel
All matches: Hydra Turquoise equivalents · Stegadon Scale Green equivalents