People who are new to the world of betta fish are sometimes surprised to learn that the classic betta splendens fish with long, flowing fins are always male.
The less showy female betta fish are rarely seen in the hobby and are only kept by specialists who wish to keep several of them together in an all-female tank or to breed from.
But what are the other differences between male and female betta fish? Come with me as I compare their appearance, and also explore how easy it is to keep each sex of betta fish.
Male vs Female Betta Fish Appearance
The most obvious difference between male and female betta fish is the way they look. The scientific term to refer to these differences is ‘sexual dimorphism’.
Fins and Tails
The iconic long, flowing fins associated with betta fish belong to the male of the species, and this is the main reason that they’re significantly more popular than females.
As with other fish, birds, reptiles, and mammals, it’s usually the male that needs to attract and impress a mate with an elaborate appearance and impressive displays of strength and character.
But another reason that male bettas have longer fins is for sparring with other males. When two males meet in a contest over a territory or breeding rights, they puff out their fins to make themselves look as big and intimidating as possible.
A betta with longer fins has a better chance of scaring off his opponent, hence the evolutionary adaptation.
Since females have less need for impressing a mate or scaring off their rivals, they don’t come with the lavish fins that adorn the male.
For the same reasons that we discussed above, male betta fish also tend to have brighter, more striking colors than females. In their native habitat, wild betta fish typically have emerald and dark red colors, but modern breeds of domesticated bettas come in every color imaginable.
While some captive-bred betta fish are pure white or pure black, when there is color present, males will normally be more colorful fish than females.
As well as having longer fins, male betta fish also have larger bodies than females.
If we exclude their fins from the measurement, male betta fish typically grow to around 2.5-3 inches long. Using the same measurement, females usually only reach around 2-2.25 inches long, making them significantly shorter.
To compensate for their shorter body, however, females are often noticeably wider than males, especially when she’s full of eggs!
A more subtle difference between male and female betta fish is the ‘egg spot’ that’s present in females but absent in males.
This tiny spot is located between her ventral and anal fins and is the point from which she lays eggs during spawning. The scientific name for this part of her anatomy is the ‘ovipositor’.
Sometimes the egg spot is so small that you’ll need a magnifying glass to spot it!
When a female betta is ready to breed, her body will prepare eggs for fertilization and she’ll often develop what are known as ‘breeding stripes’ across her body.
These vertical stripes can be distinct or subtle, but shouldn’t be confused with the horizontal ‘stress stripes’ or ‘fear stripes’ that can affect both sexes. Breeding stripes are a normal and healthy part of a female’s breeding display.
A bit like with male humans, male betta fish will sometimes display a large beard. Female bettas also have a beard, but it’s much smaller.
But what on earth are we talking about? Well, the opercular membrane of course! Not really a beard, but a silky membrane that’s usually hidden under the gills of a betta fish.
In males, the beard is often so large that it will poke out from his gills a little all the time. In female bettas, the beard is only visible when flaring. More on that next!
Male vs Female Betta Fish Behavior
‘Flaring’ is the term used for a betta fish’s display when it puffs out its gills, erects its fins and makes itself look as big and impressive as possible. While both male and female betta fish exhibit flaring behavior, they do it for slightly different reasons.
Male betta fish use flaring primarily as an intimidating display to scare away a rival male. They will sometimes also flare at their own reflection, imagining it to be another betta fish!
Female bettas, on the other hand, mainly use flaring to assert dominance over another female or other fish.
Sometimes male and female bettas will also flare at one another during courtship, which isn’t surprising, given what an aggressive and potentially dangerous affair it can be!
Swimming Ability and Jumping
Have you ever noticed that your male betta’s long fin appears to be creating drag and slowing him down?
While his fins may be very good for impressing humans and female betta fish, they’re not the most efficient design for streamlined swimming. Modern breeding has only accentuated this tendency even further.
This means that female betta fish are significantly better swimmers than males and also have a greater capacity to jump out of the tank! Males can sometimes do this too, especially in plakat betta males which have shorter fins.
Whether you keep male or female bettas, always be sure to keep a tight lid on, just in case!
Building Bubble Nests
Like gouramis, betta fish breed using bubble nests. These floating, foamy constructions also often utilize floating plant material to create a safe haven for fertilized eggs to be kept and hatched out.
But unlike many species of bird, it is the male betta fish who constructs the nest rather than the female! By using his sticky saliva and collecting air bubbles, he makes his nest at the water’s surface in preparation for mating.
Interestingly, male bettas will display this behavior whether a female is present or not. In the wild, males create bubble nests as a way to attract females, so perhaps in an aquarium, he is just waiting for his dream girl to come swimming around the corner!
Male vs Female Betta Fish Aggression
As you’ve probably understood by now, male bettas are generally a lot more aggressive than females!
It should be noted though, that temperament varies enormously between individual betta fish.
Aggression in Male Betta Fish
While some males can live fairly harmoniously with other community tank species like tetras, guppies, shrimp, and snails, others will attack just about anything that moves and need to be kept alone!
But no matter how peaceful they seem, male betta fish should never be kept in the same tank together. Their other common name ‘Siamese fighting fish’ tells us everything we need to know about two male bettas in the same tank – they’ll often fight to the death.
Aggression in Female Betta Fish
Female bettas are typically less aggressive fish and can sometimes be kept in groups – if the chemistry is right.
An all-female tank is known as a ‘sorority tank’, and these types of setups are popular with people who want to keep multiple betta fish in the same aquarium.
But female sororities are not always plain sailing. Female bettas still have plenty of fire in the bellies and can sometimes fight with each other just like males can, especially if they’re kept in a cramped space without enough hiding places.
To reduce the likelihood of aggressive behavior in a sorority tank, try to introduce all the females at the same time, and provide lots of plants and large caves for them to hide in.
Since smaller groups of females encourage bullying, I’d recommend never keeping less than 5 of them, and for that, you’ll need a tank of at least a 20-gallon capacity.
Male vs Female Betta Fish in a Community Tank
Since female bettas are less aggressive, you’d expect them to be better community tank members with other tropical fish, right?
Well, not always. Female bettas can be quite assertive in a community tank and because they are more fast and agile, they can chase and pursue other fish more persistently than males can.
As well as slowing him down, the long fins of a male betta fish can sometimes prove too much of a temptation for other fish to resist.
For this reason, bettas should never be kept with notorious fin nippers like barbs and serpae tetra. Even more benign fish like neon tetras and guppies can occasionally nip a betta’s fins, especially when they’re stressed.
Overall then, there are pros and cons of keeping both males and females in community tanks, and a lot depends on individual temperament. Whichever you choose, your other tank members need to be chosen very carefully. That’s why we compiled a dedicated top 10 tank mates for betta fish list here.
Keeping Male and Female Betta Fish Together
As well as being impossible to keep with other male bettas, you can’t keep males with females, either.
Although putting males and females in the same tank is necessary for breeding, this is usually only done very briefly, for the minimum time possible.
Breeding betta fish is a very skilled affair, a fine art best left to experienced betta keepers and professionals. Because males are bigger and more aggressive than females, they will often attack a female before or after mating, and sometimes fatally.
You can find out more about breeding betta fish from our breeding archive here.
Are Male or Female Betta Fish Better for Beginners?
Because keeping multiple betta fish is fraught with problems, I’d always recommend first-time betta keepers choose a single fish.
Whether your single betta is male or female doesn’t much matter, but 99% of people keeping a single betta fish will choose a male for his longer fins and brighter colors.
The main reason people go for females is when they want to keep several of them in a sorority tank, but I’d only recommend this venture for advanced fish keepers.
Sorority tanks are more difficult than many people realize and require a subtle understanding of fish social behavior and a high level of dedication to keep all fish safe and happy.
If you want to keep multiple pets in your tank, I’d advise instead to go for a single betta in a 10-gallon tank with some snails and shrimp, or a 20-gallon tank with some peaceful shoaling fish such as cory catfish, kuhli loaches, or harlequin rasboras.
Male vs Female Bettas for Small Fish Tanks
Once again, since males are normally kept alone, they’re more suitable to be kept in smaller tanks than a female sorority.
While people have tried to keep female sororities in 10-gallon tanks, I’d say it’s far too small. For a peaceful dynamic, you need to keep at least 5 females together, and for that, you’ll need a 20-gallon tank to give each fish its territory.
Male bettas can be kept in tanks as small as 5 gallons, but I’d suggest that a generously planted 10-gallon tank will offer more pleasure to both you and your fish.
Buying: Male vs Female Betta Fish
Looking around in your local pet store, you may even wonder where you can find a female betta fish! The vast majority of fish on sale are long-finned males.
But if you have your heart set on keeping female bettas, don’t give up. Larger stores do stock them, and they’re also available to buy directly from betta breeders.
As for pricing, the cost of male and female bettas tends to be similar when purchased from fish stores. You may, however, be able to pick up females more cheaply if you go directly to the breeders.
There are all kinds of differences between male and female betta fish, indeed they are different creatures altogether!
While the main reason that people choose females over males is the possibility to keep them together, all-female tanks are more tricky than many people realize and should only be attempted by specialists.
For beginners, I’d recommend a single male betta with some robust tank mates such as snails and shrimp.