ΔE 10.8, fair: the same colour family, but not a straight swap. The Fang is a little lighter, warmer than Fluorescent Blue. They are different kinds of paint: AK Interactive Fluorescent Blue is a fluorescent or effect paint and Citadel The Fang is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). The Fang is a little lighter, warmer than Fluorescent Blue. They are different kinds of paint.
The same difference applies the other way round: Fluorescent Blue is a little darker, 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 Fluorescent Blue on the colour wheel See The Fang on the colour wheel
All matches: Fluorescent Blue equivalents · The Fang equivalents