ΔE 17.1, loose: different enough that you should pick on purpose. Fluorescent Orange is much more saturated than Magmadroth Flame. They are different kinds of paint: Citadel Magmadroth Flame is a one-coat contrast-style paint and Pro Acryl Fluorescent Orange is a fluorescent or effect 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 17). Fluorescent Orange is much more saturated than Magmadroth Flame. They are different kinds of paint.
The same difference applies the other way round: Magmadroth Flame is much more muted.
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 Magmadroth Flame on the colour wheel See Fluorescent Orange on the colour wheel
All matches: Magmadroth Flame equivalents · Fluorescent Orange equivalents