ΔE 7.4, close: similar, with a visible difference side by side. Fluor Blue is more muted, warmer than Tyran Blue. They are different kinds of paint: Citadel Tyran Blue is a wash/shade and Green Stuff World Fluor Blue is a fluorescent or effect 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 7). Fluor Blue is more muted, warmer than Tyran Blue. They are different kinds of paint.
The same difference applies the other way round: Tyran Blue is more saturated, 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 Tyran Blue on the colour wheel See Fluor Blue on the colour wheel
All matches: Tyran Blue equivalents · Fluor Blue equivalents