I assume that you intended to ask why your male betta isn't blowing a bubble nest. Male bettas blow bubble nests when they are happy and ready to mate. some build them easier than others, some wont even build one until they see the female or even until they are actually fertilizing the eggs. To encourage your betta to build a bubble nest, be sure he has enough room (at least 2.5 gallons) not a lot of surface motion on the water, make sure the water is at least 78*. You can also let your betta flare at his reflection by putting a mirror up against the glass. this is good exercise and may kick start his territorial instincts and encourage the building of a bubble nest.
Some male betta fish are not as aggressive as others.
male
Yes. Betta Fish do change their coloer every now and then. Or if you have a male, he will change his coloer if hes chaseing a female Betta Fish. Or if he sees another male Betta Fish.
yes
She breeds with a male Betta Fish.
None are recommended if the Betta is a male.
Male Betta's are solitary. They cannot be placed with other fish. That's why they are known a Japanese fighting fish. They will kill other fish for territory.
No. Betta fish will attack each other no matter the sex.
Yes they will.
The Betta fish want to kill eachother. That's what all Betta fish want to do, that's a natural thing.
Because it's a shortfin male betta. There are such things, and the problem with them is they look a lot like females.
No.