Hey everyone. Im to breed some black neon tetra. But I don't know how to tell if I have a female on

[Toddy followes]

How to tell the sex,s of black neon tetra

 

[Byron]

There are no external gender differences, but size/shape can be a clue. When viewed from above, females will be rounder in appearance and males slender/thinner. Sometimes this is obvious from the side as well, especially if the female is developing eggs.

You can read about spawning this species under the "Reproduction" section of this profile:
http://www.seriouslyfish.com/species/hyphessobrycon-herbertaxelrodi/