Swordtail fish is one of the most popular fish among aquarists. Both new and old hobbyists love swordtails mostly because they are easy to care for and their appearance. In addition, they come in a variety of colors and patterns, each unique from the other. Moreover, the tail of the male swordtail makes it more beautiful. But, you cannot differentiate male swordtails from female swordtails when they are babies (fry). So, how long does it take for a swordtail fry to show its gender?
You have multiple answers to this question. Some swordtail fry show gender at a normal age, i.e., between four and six weeks of age. Whereas some bloom late at around eight to twelve weeks of age.
We have also seen cases where female swordtail fish have changed into a male. So, you do not have a definite answer to the question. The major way to identify males and females is the sword-like protrusion in the swordtail males. But, sometimes, Swords come out late.
So, the best way to know the gender of your swordtail fry is to look for gonopodium. The gonopodium is the sexual organ in males. Thus, if your fry develops gonopodium at around 4 to 6 weeks, it’s a boy!
Various factors determine the pace of development of swordtail fish. Some lead to the early development of genders too. We will discuss all related issues on swordtail fry gender identification in this blog post. So, keep reading!
How Long Does It Take For Swordtail Fry To Show Gender?
Swordtail fish are livebearers and give birth to live fry, at least 80-100 at a time. But, like humans or other animals, their gender is not pre-determined. All swordtail fry are born the same. They all look like clear, transparent tadpole-like creatures. It is later that they show their genders as they eventually start growing.
Swordtail fry takes around 2 months to show their genders. Some, however, can be late bloomers and can show the gender characteristic change a little later. Under normal circumstances, you will identify whether your swordtail is male or female within 2 months of birth.
Some will sex out in approximately 4-8 weeks, while others may take a little longer. Because they normally don’t start getting swords until later, you’ll have identified their sex by looking for gonopodium.
When is the Best Time to Sex Swordtail Fry?
I had problems sexing fry when I initially started breeding swordtail fish. But as I learned more about them and saw swordtail kids grow, I became much more adept at spotting the distinctions.
If you’re confused at first, don’t worry; after a few tries, you’ll be able to spot the differences between the genders rather readily.
All swordtail fry, regardless of gender, appear the same when they’re born. So it’s impossible to distinguish which is male and which is female.
As they grow older, distinctions begin to emerge. These variations are minor at first, but as the growth accelerates, they become more evident.
Within 4 weeks, or as soon as they reach a size of at least half an inch, you’ll see that fry that appeared the same a few weeks before are beginning to have distinct characteristics.
As a result, the optimal time to sex swordtail fry is when they are roughly a month old, when the tiny distinctions become more apparent, and you can clearly determine their gender.
If you’ve been watching them grow and develop for a while, you’ll see differences right away, even if you don’t know what to look for.
Correctly identifying the gender of your swordtail fish and fry has several ramifications that are best recognized early on to avoid an aquarium overrun.
How Can You Identify Male Or Female Swordtail Fry?
While it is difficult to distinguish swordtail males from females when they are still small and lack colors, certain signs can help you identify. Some of those signs are:
Gonopodium In Males
It’s better to wait 2-3 weeks to correctly identify the anal fin in male swordtail fry because female and male swordtail anal fins look identical at 1-2 weeks.
The gonopodium, also known as an anal fin or “gonopod,” is a male fish with little hooks that you can use to assist sex your fry as they grow up. These hook-like features also aid the male fish in retaining its mate during mating.
You’ll be able to tell the gender of the fry without a doubt after the gonopodium appears.
Coloration
Another sign to identify male from female is the coloration of your fry. Swordtail males are more colorful than your females. It is to attract female swordtails for mating purposes. So, coloration helps you identify male fry. They are bright and develop various patterns.
Female swordtail fry is less colorful than males, so any color development on the body of a swordtail fry indicates that it is a male. If there are only weak streaks of color on the tail, they are almost certainly females.
Growth Rate
Males tend to bloom late, so it is impossible to determine the gender of your swordtail fry until they fully develop 3-4 weeks. Swordtail gain sexual maturity at 3 months of age. So, males develop gonopodium by the 3 months. Swordtail females mature earlier than males. They are also comparatively bigger than the female. So, female swordtail fry may show gender characteristics early on.
Swords
One major way to differentiate male from female is the long sword-like protrusion in the caudal fins of male swordtail. On the other hand, the female swordtail has a rounded tail and lacks the sword. However, since the swords develop only after 12 weeks or so, it can be difficult to identify the gender of the swordtail fry based on swords.
Gravid Spot
The gravid spot, located at the base of the tail, indicates where the fry will grow when the female swordtail becomes pregnant.
Female swordtails have a dark-colored mark on their backs that grows more noticeable as they get older.
Beginners might not notice it right away, but a skilled breeder can discover the gravid patch in swordtail fry early on.
If it’s a female swordtail fry, look for a dark spot near the belly and anal fin to identify the gravid spot.
In this way, you can identify male swordtail fry from female swordtail fry.
Why Should You Separate Swordtail Fry By Gender?
As I previously stated, correctly identifying the gender of swordtail fry is critical whether you wish to stock the aquarium with only one gender, sell them, or have them reproduce.
But there’s another reason behind it that’s just as essential, especially regarding growth rates.
Separating swordtail babies by gender is an effective strategy to boost swordtail fry growth and keep them alive. That’s because they’ll be able to breed as soon as they achieve sexual maturity (about 3 months).
Breeding will consume a lot of energy and may slow down their growth pace, which you want to avoid if you plan to sell them.
Other than separating swordtail fry by sex, there are other strategies to speed up their growth, such as giving them enough space, feeding them a varied and high-quality diet, and ensuring their water is clean and well-maintained.
While it is vital to separate them by gender to stimulate their growth, it is also true that this is not the only technique to help them grow quicker, and you should also aim to provide them with the finest possible surroundings.
Are Male Swordtails Late Bloomers?
Their distinctive swords characterize swordtail males. The swords take a while to grow. That is why we can consider that swordtail males are late bloomers. Male swordtails are more colorful than females, but they are about an inch or two shorter. Thus, they take more time to develop their sex.
Swordtails have been reported to go over 6 months without showing their sword or gonopodium. So you might be thinking that your swordtail fry is a female when suddenly she will start growing the tail and suddenly she’s a he! Most people can tell at 3 months, but my friend has one swordtail that has just started to show as a boy and is nearly 8 months old.
Male swordtails don’t usually get their characteristic male color until they’re about three weeks old.
They don’t have any gonopodium ridges (distinguishing traits) till that period as well. So that’s why it’s crucial to be patient and sex your swordtail fry after at least three weeks.
The only thing you need to keep an eye on is the color of your fry and its rate of growth. The practice of overfeeding is also a useful way to distinguish the genders of swordtail fry.
FAQs
Here are answers to some of the most asked questions:
Do Swordtail Fish Change Gender?
Swordtail fish can change genders. Some late-blooming males may develop their distinctive tails later in their development. However, after giving birth, a female swordtail fish can transform into a male.
Unlike most other fish, Swordtails have a more complicated sex determination process since their sex is determined by the temperature at which they are born rather than their chromosomes. In addition, swordtails belong to a group of fish known as protogynous hermaphrodites, which means they can change gender.
Should I Separate My Swordtail Fry?
Yes, it is best to remove the fry from their spawning tank. However, if you leave them with their mother, she may regard them as food and consume her kids!
Should I Separate Female Swordtail Fish?
Well, that is all up to you. Most people prefer to keep their female Swordtail fish separate from their male Swordtail fish. This is because when there are several in a tank together, they tend to fight for food. On the other hand, a single female can be kept in an aquarium by herself with no issues as long as she has enough room to swim around in.
No, unless the tank is overloaded, you don’t need to separate a female fish from her male spouse. It’s better to share the same tank if you have male and female swordtail fish ready to procreate.
Conclusion
Therefore, determining gender in a swordtail fry is pretty difficult at first as they both look the same. Therefore, you should wait at least a month or two before your swordtail fry show gender.
Gonopodium, gravid spots, and coloration are some factors to consider while identifying males from female swordtail fish. It is important to separate the genders because genders play a huge role in breeding swordtails.
If you keep male and female swordtails together for over 3 months, they become sexually mature and ready to breed, which causes a problem if you aren’t looking to breed them.
That is why identifying genders and separating them is essential.
