Betta fish are one of the most popular tropical freshwater fish in the aquarium hobby. These charming little fish come in myriad different colors and forms, and you can breed them at home relatively easily too.
Now, if you want to try a fun breeding project with your betta fish, you’re going to need one male and one female betta fish.
But how do you tell the difference? Do male and female bettas look alike? And do they behave the same?
Read this guide to learn how to tell if a betta fish is male or female and more!
Wild Fish vs. Pet Betta Fish
There are around 73 different betta fish breeds, including wild and domesticated varieties, and the first thing to know is that wild bettas look totally different from those bred for the pet trade.
Male wild betta fish don’t have the spectacular fin and tail shapes or the dazzling range of colors that you see in their domesticated cousins. In fact, wild male betta fishes are usually a rather drab brown or grayish-green color with short, stubby fins.
Wild female betta fish look much the same as males, although they tend to be a little smaller.
Wild betta fish are said to have a weak “sexual dimorphism.” That means it’s extremely difficult to tell the two sexes apart.
However, in captive-bred domesticated betta fish, sexual dimorphism is very strong because males are completely different in their behavior and look than females. The main attraction of having a betta fish as a pet is its glorious colors, iridescence, and spectacular fin shapes. That only occurs in males, while females remain comparatively drab and unexciting.
Where you buy your betta fish can clearly indicate the fish’s gender.
Whenever I visit my local pet store and tropical fish section in our local garden center, I’m drawn to the display of bettas housed in a row of small cube tanks.
These Siamese Fighting Fish are always brightly colored with tail shapes such as half-moon, veiltail, and crowntail. Many are marbled, patterned, or have metallic scales that sparkle in the shop lights. That’s not only impressive but tempting if you have the space for a betta in your collection!
Female Betta Fish
Across the aisle is another row of tanks containing smaller betta fish that are somewhat plain to look at and don’t have the aesthetic appeal of the others. Some onlookers mistake these for male juvenile fish, but they are actually females.
Of course, many high-street pet stores only sell male bettas, and it’s often more specialist aquarist shops or online breeders that sell females.
For that reason, I recommend that you ask the store assistant to confirm if the fish you’re considering purchasing is male or female if you’re not sure. An experienced store clerk should be able to tell you what sex the fish is, so don’t be afraid to ask.
Physical Differences in Appearance
Female and male betta fish are totally different in appearance.
Male betta fish have exaggerated finnage, bright colors, and patterns and are often metallic. In comparison, female bettas are typically drab and dull in color with shorter, rounder fins.
That said, some female betta fish are quite colorful fish, so color alone is not a clear indicator of the fish’s sex.
Female betta fish have vertical stripes on their bodies when ready to spawn, while males don’t generally have them.
Horizontal stripes on betta fish are a reaction to stress or poor water conditions. So, when you first bring your betta fish home from the pet store, you might notice that the creature’s colors fade and light or dark horizontal stripes form on its body.
Most hobbyists and betta experts agree that breeding stripes run vertically, whereas stress stripes run horizontally.
To confuse matters, stress stripes are usually much more obvious in female bettas than in males!
Body Shape and Size
Female bettas usually have wider, stockier bodies than males, which are typically slimmer.
Male bettas are usually 2.5 to 3 inches long, while females are slightly smaller, measuring 2 to 2.5 inches long.
As mentioned above, male betta fish are known for their long, elaborate fin forms, which can be up to four times the length of those in female fish.
Although some species, such as Plakat betta fish, have short tail fins, in almost all varieties, females have short caudal fins compared with those of males. Male bettas have longer, thicker ventral fins than females.
Mature female betta fish have what’s commonly termed an “egg spot” between the anal and ventral fins.
That spot is actually the fish’s ovipositor that the female betta uses to deposit her eggs. Unlike in other species, male bettas don’t generally display an egg spot, although it’s not unheard of.
Betta fish have a membrane under the gill plate cover that’s commonly called a “beard,” although the proper name for the structure is the opercular membrane.
Although both sexes have a beard, the male’s is much larger and more obvious than the female’s, especially when the male fish flares his gill plates.
Male vs Female Betta Behavior
So, male and female betta fish are very different in appearance, but what about their behavior?
Male bettas typically flare in response to perceived threats and sometimes during courtship. When male betta fish flare, the beard is displayed to full effect as a means of intimidating a rival or frightening away an intruder to the betta’s territory.
Female bettas also flare, although their beard is much smaller. In addition, female bettas usually flare in a head-down position, which most male bettas don’t adopt.
Male bettas are also called Siamese Fighting Fish, and there’s a very good reason for that.
These highly territorial, aggressive fish will patrol their adopted territory and defend it from all comers. In the wild, that sometimes results in violent fights and even death, which is why you must never keep two male bettas in the same tank.
Sometimes that aggression can be aimed at a single female betta, so most hobbyists only keep one male betta in isolation unless they specifically want to breed from their fish. Once the eggs have been deposited and transferred to the male’s bubble nest, the female should be removed for her own safety.
Female betta fish can live in a sorority of up to five to prevent a weaker fish from being bullied by the dominant female.
I once kept a small group of four females with one male betta in a community tank, which worked for me. However, such an arrangement’s success depends on the male betta’s temperament and is not guaranteed to rule out aggressive behavior completely.
Male bettas are much more aggressive characters than females.
That said, females can be aggressive toward each other, especially if only two fish are in the group. Often, the more dominant female will pick on and bully the other, so it’s always best to keep a small group of up to five female bettas so that bullying is less likely.
Bubble Nest Building
Male bettas build a bubble nest regardless of whether females are present in the tank.
The male blows bubbles that gather on the water’s surface, typically in a corner of the tank or under plant leaves. When the female lays her eggs underneath the nest, the male fertilizes them and carries them up to the safety of the bubbles. He then guards the nest until the eggs hatch and the fry are free-swimming.
For the female’s safety, it’s best to use a breeder box or keep the bettas in separate tanks once spawning is complete.
A female betta fish will occasionally blow a bubble nest, but that’s usually the male’s job!
When it comes to life expectancy, both sexes share much the same lifespan of two to five years, depending on living conditions, diet, and tank mates.
It’s important to know that fish of both sexes have a much shorter life expectancy when living in stressful conditions. So, pay close attention to keeping your betta tank clean, nicely decorated, and well-oxygenated, and feed your fish a varied, high-quality diet to keep stress levels to a minimum.
Both male and female betta fish have a labyrinth organ that enables the fish to breathe atmospheric air at the water’s surface. That adaptation enables wild betta fish to survive during drought conditions when the water is shallow, stagnant, and not well-oxygenated.
Note that the ambient temperature must be as close to the water temperature as possible if the labyrinth organ is to remain healthy.
Did you enjoy our overview of how to tell the difference between male and female betta fish? If you did, please take a moment to share the article with other betta beginners before you go!
Male and female bettas look and behave very differently, so it’s quite straightforward to tell the difference between the two sexes. Males are usually much brighter in color and have longer, more extravagant fins, whereas female betta fish are slightly smaller and less vibrantly colored with smaller fins.
Female betta fish have an ovipositor or egg spot that’s usually absent in males, and they often develop vertical stripes when in spawning condition, which males don’t typically have.
Do you have male or female bettas? Why not tell us about your fish in the comments box below?