Specifically, when should the elongation of the tail in males start? I've had four survive a birth in mid-June and don't know if I'm able to say they're all females just yet or if the males will start showing themselves in a month or two.
When can I determine the sex of swordtails?
- Thread starter Luke Jaywalker
- Start date
The sword is not the best method for sexing, look at the anal fin. Females will have a triangular shaped full anal fin, while the males will lack that and have a stick like fin called a gonopodium. You should be able to sex the fish at 2-3 months easy.