The swordtail is a popular member of the swordtail fish family. Its streamlined body and long, sword-like fins give them maneuverability in its constantly changing aquatic habitats. There have been long-term debates on whether swordtail fish can change their gender. But, how true is it?
Swordtail fish do change genders. There can be some late-blooming males that develop their signature tail later during their growth. But, a female swordtail fish can turn into a male after giving birth.
If swordtail fish can change gender, what is the process, and how does it affect swordtails? Let’s get started!
How To Distinguish Male Swordtail From A Female?
You can easily tell swordtails apart from their fins. First, male swordtail fish have long, sword-like tails. Second, they have a distinctive black stripe along the length of their body.
Another way to distinguish male swordtails from females is to look at their anal fin. Males possess “pre-anal” fins that are longer than the anal fin. Females don’t have this feature.
In swordtail fish, the male swordtails usually have slimmer bodies than females. And their sword-like tails are shorter and more pointed compared to their female counterparts.
Can Swordtail Fish Really Change Gender?
Swordtails start as one sex and end up being another. This is actually a pretty common occurrence among swordtail fish. In swordtails, the sex of an individual swordtail is determined by whether they have XX or XY chromosomes.
The swordtail with two X chromosomes develops as a female, and swordtails with one X and one Y chromosome become males. As far as we know, swordtail fish are born as males, but swordtail fish can change gender.
How Do Swordtail Fish Change Gender?
Swordtail fish can change gender when they are unhappy with their tank setup or imbalance in the swordtail population. When this happens, a swordtail female will show characters of a male, and male swords will start to develop ovaries.
Strangely, swordtails can change gender — swordfish have a more complex process of sex determination than most other fish because their sex is determined by the temperature at which they are born, not their chromosomes. Swordtails can change gender because they are part of a group of fish called protogynous hermaphrodites.
This means swordtails can change their genders when needed to maintain the population in their tank and swordtail fish species.
Likewise, female swordtail species can change into males, so they do not need to find another male partner if one dies.
Why Do Swordtails Change Sex?
The swordtail fish actually changes to the opposite sex if there are not enough of its own kind. Under normal circumstances, a female swordtail can become a male swordtail when exposed to too many male swordtails in her swordtail tank. But why do they do so?
So, swordtails change gender to try and maintain the population of swordtails in swordtails tanks by breeding with other swordtail fish. This is an example of when swordtail fish change gender.
A Female Swordtail Can Change Into A Male Swordtail
Females can change gender into a male swordtail, but this is very rare in swordtail fish species. A swordtail female can change its gender from female to male when it has lost all of its female swordtails (her mate and her offspring).
Two possibilities can lead to swordtail fishes gender-changing:
1. The swordtail female – the lone swordtail, is left by its swordtail male partner. This may be caused by the swordtail male being attacked or eaten by another swordtail fish species or bigger predator (fish, birds, or mammals); and
2. The swordtail female is left without a swordtail male swordtail to mate with because its swordtail male partner lost in a swordfight against other swordtails.
In both situations, swordtail female swordtails are left to fend for themselves. They no longer have the swordtail male swordtail as their mate or parental swordtail fish to protect swordtail fry.
The swordtail female cannot reproduce naturally anymore – they produce infertile eggs after reaching sexual maturity at 1 year of swordtail life. This means swordtails cannot produce swordtails of their own species to take care of them for the rest of their lives.
What does this mean? If they do not find another swordtail male partner, they will soon die because swordtails are social animals that need to survive. So, to save itself from imminent death, the swordtail female swordtail can turn into a swordtail male swordtail and change its gender!
When Are Swordtail Fish Likely To Change Gender?
Swordtails get stressed out if they do not have a lot of room in their tank. In addition, swordtails are a susceptible fish species to stress, and swordtails can change gender in response to stress.
A swordtail female may become a male swordtail if she is not happy with her tank set up because there is not enough space or food for the number of swordtails inside sword swordtail swordtails tank.
This swordtail female swordtail is becoming a male swordtail because her swordfish environment is too stressful!
How to Tell If Your Swordtails Have Changed Genders?
There are some easy ways to tell if you have swordtail swordtails that have changed genders:
Look at their behavior
swordtails that have changed sword swordtails genders are aggressive and territorial. Swordtail of the opposite gender will act as if they see another swordtail fish species entering their territories, even if they are swordtail swordtails of the same sex.
See how much territory each swordtail has in the tank
Swordtails that have changed gender tend to claim many swordtail tank territory and do not share it with other swordtail fishes (of the same sex or opposite swordtail fish).
Building Bubble Nests
A swordtail female swordtails that have changed swords into a male swordtail will start to build bubble nests. Male swordtail fish do this when they are ready to mate with female swordtails.
What Can Other Fish Change Genders?
Swordtails are not the only fish that can change sword swordtails. Some other fish species that have been known to change sword swordtails include:
– clownfish
– hermaphrodites (most fish)
What About the Swordtail Fish Fry?
Swordtail fry (baby) will behave the same as any other swordtail of their own species. They won’t change gender, even if they are in an environment with too many swordtails or where there aren’t enough swordtail species.
Read Also: How to take care of swordtail fish fry?
Conclusion
The swordtail gender change is imposing in the swordfish world — swordfish do not really exhibit many male or female traits until they are fully developed. So though swordtail feminization is common, it’s rare to see a complete sex swap happen.
There are various environmental, physical, and mental factors responsible for a gender change in swordtails. This fact should be further experimented and studied for reliable results.
