My betta marley has never seemed very agressive. Since I got him when we would put a mirror next to his bowl he would just look at it and mabye swim a little fast but he didnt seem very interested. I thought this was normal until I got poseidon. I put poseidon's bowl right next to marley's tank and a while later Poseidon had his gills(mabye they werent his actual gills but they looked like it) completely sticking out and he was swimming crazily towards marley. And marley was just swimming regularly. Is there somthing wrong with him? Or is he just a very nice betta

I think Marley is probably just less aggressive than others.

My Chocolate is very un-aggressive. He never flares at anything. My other two however love flaring and building bubble nests.

It is funny how bettas have their own personalities. Some are less aggressive than others. Vanilla, who is appropriately named, is very unaggressive. I think I have seen him flare once, very half-heartedly. Whereas, Cinnamon, who is aptly named also, loves to flare. Go near his tank, and out goes the gills

And then there's the narcissistic personality type... Our betta Mo repeatedly dives to admire his reflection in the heater and comes back up and blows bubbles.

Im sure he is alright.Some bettas are not very
agreesive.
the gills you were talking about that were poping out
that is called flareing.
They do this to scare off other males ect ect.

Oh I thought flaring was just when they pread out their fins haha.