ΔE 7.7, close: similar, with a visible difference side by side. Aegis Aqua is more saturated, cooler than Sky Blue. They are different kinds of paint: AMMO by Mig Sky Blue is an ink, glaze or transparent paint and Army Painter Aegis Aqua is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Aegis Aqua is more saturated, cooler than Sky Blue. They are different kinds of paint.
The same difference applies the other way round: Sky Blue is 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 Sky Blue on the colour wheel See Aegis Aqua on the colour wheel
All matches: Sky Blue equivalents · Aegis Aqua equivalents