when they get frightened or scared. sometimes when their annoyed
you can tell if its a boy or girl by the fins the male Betta has long fins and the female Betta has small fins
A female betta has very small fins with a long body while the male betta have lots of nice flowing fins.
Male betta's are larger, more colorful, and have much longer fins. Female betta's are small, less colorful, and have short stubby fins.
usually a male has longer tail fins but they are about the same for side fins
Male betas are colorful and have large fins. Females have virtually no fins and have no color
Your betta fish is a female if she has smaller fins than an average male.
My Betta has swelling under it's front fins below it's gills.
A Crowntail Betta Splendens is a variant of Splendens that has parted fins in a way that makes them look appealing. it is simply something you must look up on google images to get the right answer Fightn' Fact: There isn't only one Betta. Betta is an entire Genus of fish that qualify for certain specimens of fish. The fish you are talking about is betta splendens
Yes; fish fins can regrow and heal with amazing speed.
There are so many different colour variations of Betta that red streaks in blue fins are quite common as are blue streaks in red fins. All it means is that the fish are cross bred.
This is not a Betta question so it belongs elsewhere.
the size of it's fins and body