One of my bettas wont flair up when he sees himself or another one of my betas

Question
Hi there,

I have six male betas, that are all so beautiful.  I keep them in separate tanks so that they wont hurt each other or themselves, and when I clean their tanks I make sure that they are never put together.  My question is, one of my betas doesn't flair up his gills when he sees any of the other five.  If they are close enough to each other (which is rare) they all will puff out.  I have noticed though that he wont.  I even tested it to see what he would do, and while my other beta flared out, he just did nothing.  I know he saw the other one too because he literally just stared at him.  He is very active, he eats well.  I read from one of bentys answers if your beta doesn't flair up when he sees another beta then something is wrong -- but they didn't say what it would be.  I also noticed that he is what it looks like blowing bubbles.  He comes to the top and blows bubbles on the top of the water. Why is my beta not responding to others and blowing these bubbles which I haven't seen the others do?

Answer
Simple answer, all fish have personalities. This is a proven scientific fact, not just my own observation.

He is just more peaceful in nature than the other bettas, but that doesn't mean you can ever mix them in the same tank.

These bubbles are called a bubble nest. The males do it when they are happy and comforatable, in hopes that some female will swim along and lay eggs in his bubble nest. If your other bettas are not doing this, there is likely something wrong with the water quality or what you are feeding them. Either that or they are just simply not sexually mature.

-Nick