Clownfish Behaviour

[Gujustud]

So my clownfish are doing just as good as when I first got them. They have grown quite a bit, and colors are much brighter now.

However, for the last week, I've noticed they almost seem to fight a lot more often. Always squaring off head to head, nit-picking at each other. They'll be swimming around side by side, then all of a sudden start fighting. Is this a normal behaviour? Are they reaching sexual peak? Is there such a thing as clowns not pairing off?