Why is Natsu and Gray always fighting??? Is it because of Lucy or Strenght

Natsu and Gray are fighting since they were childhood friends. They were called rival friends. Also their powers are opposites like Ice vs Flame or Fire. And it's like they are showing off their powers. Like who's the strongest! Natsu or Gray! Like that. And for those who believed that their fighting because of Lucy then go don't stop believing cause everyone of us can have our very own version or opinion. And that's how I put it to words. Usually they are just showing of their powers.

Natsu and Gray fight because, I think, that their Magics', Fire and Ice, are opposites. And as they've known each other since they were children, they've become somewhat like brothers, and, like brothers, they quarrel.

There like brothers that fight so the time and plus fire and ice are opposites

I dont think it is Lucy because they both are always fighting even from their childhood. Its like friendly rivals because they do help each other a lot . may be to prove that himself is more stronger.

Natsu and Gray always fight is because fire and ice doesn't go together and they always fight when they were little, so yeah it's now because of Lucy or strength