This thread has gone to the dogs .lol I'm a Doberman lover and know nothing about pit bulls, other than the myths. But I believe all dogs will behave accordingly to the way they were brought up/trained.
Back to the betta ....hope I don't get kicked out of the internet again.....
So for the fourth time in the last few days....
I differentiate viciousness, aggressiveness, and mentality. First is a character that would shred others to pieces but would not fight long. Second is a character that would chase away and fight for territory but not necessarily vicious. Third is a character close to aggressive - it is the strength of the fish's self esteem but not necessarily vicious nor aggressive. It would fight to the bitter end if challenged but not always chase away others.
This is based on past experiences (mid 70's to early 80's) with the classic fighters and VT. It's inconclusive to relate colors to character other than mentality. IMO dark colored, such as green and specially black lace based, tend to show stronger mentality compared to other colors. Light colors and dark colors which carries (the ones used to mix to light color) light color (like blue and red) show weaker mentality. (hope this makes sense)....
If a dark color becomes stressed (for what ever reason incl loose a fight) it will take them shorter time to regain their self esteem and defend their territory. Sometimes light colors never regain such mentality but becomes vicious towards younger fish or females..... you can't find light colored fighters these days.
The way they were brought up also plays a big role. Fish brought up in solitary since the age of 2 months or so and has never been intimidated by other bettas usually shows a high level of aggressiveness and often stronger mentality compared to those brought up in a sorority. But once stressed, they would never fight for long. These characters are, IMO, also related to age. An elderly betta tends to be more docile, even towards other males.
Again, this is past experience. I'm not sure of their current development. I've noticed some changes in color genetics (not character) since the early 80's and haven't had fighters since late 70's nor have I really payed attention to their character. So their characters may also be different. If you (OP) is interested in the relationship between character and color, this is something you could look into. Must warn you though, you would have to fight them to see if my past conclusion is true.