Since we often get questions about determining the sex of livebearers, I have decided to post a thread that gives you a way to judge the sex/gender of a livebearer.
A common livebearer, which includes most swordtails, guppies, platies, mollies and several similar livebearers, can be easily sexed using the shape of its anal fin. That is the fin next to where a fish eliminates its solid waste. A female common livebearer is one that has an anal fin that is more or less fan shaped. Some will call it triangular shaped.
This is a female of a species that is typical of the common livebearer. It happens to be a golden teddy but that is not really important. She is a bit hard to see but once you look at her anal fin shape, you will understand what we are looking for.
This is a male of the same species. His anal fin has been modified into what is called a gonopodium. It is an anal fin that has taken on a long thin shape that the male can use as a sex organ for delivering sperm to the female. Sometimes new livebearer people will mistake a female for a male in hifin fish because the hifin gene makes a female have a long first ray to her anal fin. She will still have the fan shape to the rest of her anal fin so she can be separated from her male contemporary.
The less common goodeids can also be differentiated based on their anal fin shape. A male has a split look to its anal fin, giving the other common name of goodeids being split fins. A male goodeid has a fin that can be thought of as the shape of a mitten. It takes on a shape that looks somewhat triangular but has a definite break so that the anal fin looks like a mitten with a distinct thumb accompanied by a main fin shape. The female, much like in common livebearers takes on a fan or triangular shape. How about some examples.
Now a male with its andropodium, the mitten shape we were talking about.
And now a female of the same species of goodeid.
This is my best way of allowing a new person to sex their own livebearer. Beware that some hifin female livebearers can have very long first rays on their anal fins and can look somewhat like a male while being functionally female. The best way to separate those fish from a similar male is that they do indeed have anal fins with the fan shape on top of a first fin ray that looks very much like a male. Sorry that I have no examples of such fish since I breed only pure species representatives of each species.
These pictures are examples from my own tanks but I do not keep tons of the common livebearers like mollies, platies, guppies or swordtails so the examples I have given are somewhat less common, but still typical, livebearers.
A common livebearer, which includes most swordtails, guppies, platies, mollies and several similar livebearers, can be easily sexed using the shape of its anal fin. That is the fin next to where a fish eliminates its solid waste. A female common livebearer is one that has an anal fin that is more or less fan shaped. Some will call it triangular shaped.
This is a female of a species that is typical of the common livebearer. It happens to be a golden teddy but that is not really important. She is a bit hard to see but once you look at her anal fin shape, you will understand what we are looking for.
This is a male of the same species. His anal fin has been modified into what is called a gonopodium. It is an anal fin that has taken on a long thin shape that the male can use as a sex organ for delivering sperm to the female. Sometimes new livebearer people will mistake a female for a male in hifin fish because the hifin gene makes a female have a long first ray to her anal fin. She will still have the fan shape to the rest of her anal fin so she can be separated from her male contemporary.
The less common goodeids can also be differentiated based on their anal fin shape. A male has a split look to its anal fin, giving the other common name of goodeids being split fins. A male goodeid has a fin that can be thought of as the shape of a mitten. It takes on a shape that looks somewhat triangular but has a definite break so that the anal fin looks like a mitten with a distinct thumb accompanied by a main fin shape. The female, much like in common livebearers takes on a fan or triangular shape. How about some examples.
Now a male with its andropodium, the mitten shape we were talking about.
And now a female of the same species of goodeid.
This is my best way of allowing a new person to sex their own livebearer. Beware that some hifin female livebearers can have very long first rays on their anal fins and can look somewhat like a male while being functionally female. The best way to separate those fish from a similar male is that they do indeed have anal fins with the fan shape on top of a first fin ray that looks very much like a male. Sorry that I have no examples of such fish since I breed only pure species representatives of each species.
These pictures are examples from my own tanks but I do not keep tons of the common livebearers like mollies, platies, guppies or swordtails so the examples I have given are somewhat less common, but still typical, livebearers.
