ΔE 15.4, loose: different enough that you should pick on purpose. Light Turquois (Phthalo) is noticeably lighter, more saturated, cooler than Coelia Greenshade. They are different kinds of paint: Citadel Coelia Greenshade is a wash/shade and Golden Light Turquois (Phthalo) is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Light Turquois (Phthalo) is noticeably lighter, more saturated, cooler than Coelia Greenshade. They are different kinds of paint.
The same difference applies the other way round: Coelia Greenshade is noticeably darker, more muted, 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 Coelia Greenshade on the colour wheel See Light Turquois (Phthalo) on the colour wheel
All matches: Coelia Greenshade equivalents · Light Turquois (Phthalo) equivalents