First Answer
She has been damaged internally. Has this female been bred recently or maybe someone has handled her a bit roughly (Squashed her). With that kind of internal damage it is highly unlikely the fish will survive for long.
A male accidentally got into her tank one day and when the owners got home she was fine but then she started growing this bulge! No she was not abused the owner is an animal lover!
Are you trying to imply that the female Betta is pregnant or something. Well that is quite impossible because Bettas are egg layers. The eggs are fertilised outside the females body under a bubble nest and the male looks after the fertile eggs until they become free swimming. Maybe the male bashed her in the stomach. What I said above still stands. She has obviously been damaged internally for part of her insides(stomach?) to be (distended) outside her body. There is no other logical explanation for this symptom.
It means he hates you. Bettas flare their gills out when they're trying to scare another betta away, or to impress a female with how large he is.
The bright colored betta is the male. The males have to be pretty to attract the female. That means the light colored betta is the female.
If you would like to know what gender your betta is, look for the egg spot. (for females) It should be a small white cloud between the head and body. If your betta has one, it's a female. If your betta doesn't have one, it's a male.
Female beta is a murderer.
Male betas are colorful and have large fins. Females have virtually no fins and have no color
Male betta's are more colorful then female's
From a female Betta. Then the male Betta fertilizes them when they breed together.
Your betta fish is a female if she has smaller fins than an average male.
If they are not too old and the female is ready, then they will mate.
She breeds with a male Betta Fish.
it depends i have a male with a female betta, in a 2.5 gallon tank,they get along, i wouldnt risk it, no
the female betta fish are released from a vent while a male embraces her