Compared to other freshwater fish species, it is really easy to tell male and female swordtails apart. Here are four easy ways to tell male and female swordtails apart.
Four Ways to Tell Male and Female Swordtails Apart
1. Male Swordtails Have Long Pointy Tails
The easiest way to tell male and female swordtails apart is to look at their tails. Male swordtails have long pointy tails. Hence, the name “swordtail.”
However, male juvenile swordtails don’t have long pointy tails. They have to reach sexual maturity to develop the long pointy tail. Male and female juvenile swordtails both have rounded tails.
2. Male Swordtails Have Gonopodiums
Another way to tell male and female swordtails apart is to look for the gonopodium. Similar to other male freshwater livebearers, male swordtails have a modified anal fin called a gonopodium. While female swordtails don’t have a gonopodium (the anal fin looks rounded). The gonopodium looks like a long, pointy anal fin.
3. Female Swordtails are Fatter and Bigger
Female swordtails are generally fatter and wider than male swordtails. On the other hand, male swordtails tend to be slender and thin. When they reach maturity, female swordtails tend to be bigger than male swordtails.
4. Female Swordtails Have Rounded Belly
Female swordtails have rounded bellies, while male swordtails don’t have round, protruding bellies. Even if the female swordtail is not pregnant, they tend to have protruding bellies because they are carrying eggs. While male swordtails are slender and thin with no protrusion in the belly area.
How to Tell Male and Female Juvenile Swordtails Apart?
It’s difficult to tell male and female juvenile swordtails apart because they look similar- rounded tails with similar sized bodies. One way to tell apart male and female juvenile swordtails is to look for the gonopodium.
Look closely at your swordtails. Look for the tell-tale signs of gonopodiums on male juvenile swordtails. They look like pointy anal fins. Male juvenile swordtails will have gonopodium even before they start to develop the long, pointy signature tail. On the other hand, juvenile female swordtails will have rounded anal fins.