you're talking about a big fire right? not just some candle light...
If you have a movie where they light a torch or a fire, try study the scene and the fire in particular.
Notice how it dances whit the wind and occasionally spits a few "pixels"
Fire also moves relatively fast, so 8 frames shouldn't be too few.
Some movies they light a fire in (where you also get the time to study it): "6 days and 7 nights", "pirates of the Caribbean", "Cast Away" and "Gangs of New York"
It's probably easier to understand whit an example ^^;