the boy bettas have big colorful fins, and the girls have small but still kind of colorful fins.
They see them the same as other male bettas,as competition,they cannot tell the diffrence between their reflections and other bettas.
the males have longer fins
if their full grown they are ready.
Male bettas have a long tail fin, and they are brightly colored; more so than the female which is a dull color. She has a short tail.
You can put that down to evolution and the survival of the species. That's all. The male is the protector and defender of both his bit of space and his progeny (fry) and he will not permit others of his gender and species to be in his space.
the gender is a guy you can tell
Your parents
No. The gender is not related to the relationship of the parents.
If that gender turns you on
If you know your rodents, you should be able to tell the gender of baby rodents at birth (I can).
Boy bettas have really big fins and are very colorful, and girl bettas are pretty much the opposite!
Bettas originate from Southeast Asia.