User blog comment:Httyd big fan/Thirty-Fifth Dragon Fight Club Match: Night Fury vs. Light Fury/@comment-34364618-20191021221717/@comment-27673013-20191128115320

While the Light Fury is smaller and more agile, this does not necessarily make it better in battle. The Light Fury is built more for flying but not fighting, with the Night Fury being stronger and more easily able to overpower the Light Fury.

While a Light Fury can use camoflauge, Night Furies can too. Assuming the battle is taking place in the training cage, the roof is open and the Night Fury would easily have access to lightning, although they do not solely rely on this. Not only is this useful for dissapearing, it also means the Night Fury could summon lightning in to strike down the Light Fury.

You also said above that a Night Fury's cloaking would wear off pretty quickly. This could only be deduced from the third movie, where it wears off on Toothless pretty fast, but this may just be because he had never tried it before, and a more experienced Night Fury could make it last longer. Near the end

On an added note, the Night Fury could also go into alpha mode, giving them added strength, speed and firepower that the Light Fury has not been shown to use.