Male vs. Female Bettas: A Guide to Spotting the Differences

Do you often wonder about the gender of Bettas with their beautiful, flowing fins when browsing in pet stores?

Male Bettas are more common in pet stores due to their vibrant colors and striking appearance, while female Bettas are often overlooked for their more subdued beauty.

Identifying the gender of your Betta fish is crucial for fishkeepers as it helps in selecting appropriate tankmates and breeding healthy fish. It’s not just about naming them Patrick or Patricia!

For a quick glance, the main differences between male and female Bettas are:

• Male Bettas have longer, flowing fins compared to females.
• Male Bettas have a pointed dorsal fin, while females have a rounded one.
• Male Bettas have a pointed anal fin, while females have a fan-shaped one.
• Male Bettas have elongated ventral fins, while females have short and rounded ones.
• Male Bettas tend to have more vibrant and intense hues compared to females.
• Check for breeding stripes (vertically) on the body. These are only present in female Bettas.
• Ovipositor also known as eggspot is commonly seen in female Bettas. However, it’s worth noting that male Bettas can often have a false eggspot, so other characteristics should also be considered when determining gender.

Let’s dive into the details of identifying their unique physical and behavioral characteristics.

Physical Differences

In the wild, male and female Bettas look very similar, which makes it difficult to distinguish between them. However, Bettas that have been raised in captivity have been selectively bred to have more striking colors and longer fins. As a result, there are now noticeable physical distinctions between male and female Bettas.

Size and Body Shape

Betta fish usually grow to 2-3 inches in length with slight size differences between males and females. Fully grown adult males are generally larger, with bodies measuring between 2.5 and 3 inches long. In contrast, mature female Bettas typically have bodies around 2-2.25 inches in length. However, it’s worth noting that juvenile male Bettas are usually about the same size as mature female Bettas.

Male and female Betta body measurements usually don’t include fins, which are crucial for distinguishing between the sexes. Males usually have larger and more elaborate fins, resulting in a significant size difference compared to females.

In addition to size, male and female Bettas differ in their shape when viewed from above. Males are typically 0.25 to 1 inch longer but are also more slender compared to females. On the other hand, females are shorter but appear wider when viewed from the top.

Fins and Colors

Bettas are a popular tropical fish due to their incredible variation in color, fin shape, and size. Breeding Bettas has resulted in an extensive range of colorations, from red, blue, and green to shimmering copper or multi-colored marble.

Fin shape and size vary significantly across different breeds, ranging from Crowntail to Half Moon. Additionally, color and fin shape are crucial characteristics for distinguishing between male and female Bettas. Let’s take a look.

Types of Fins

The size of fins is one of the main differences between male and female Bettas, with males having much larger fins and more extravagant fins than females, including the dorsal, ventral, and caudal fins (1).

Male Bettas have fins that can be up to 2-3 times the size of their bodies, sometimes reaching up to 9 inches in length. In contrast, female Bettas have fins that are generally no more than one body length, making male fins three to four times larger than female fins.

Coloration Differences

Male Bettas are more brightly colored than females, with more vivid coloration. Female Bettas tend to have a duller coloration (2).

Male Bettas naturally display vibrant colors to attract mates, a trait that has been perpetuated in domesticated Bettas. Additionally, breeders have deliberately promoted bright colors in both male and female Bettas to enhance their aesthetic appeal. As a result, it’s common to find female Bettas in captivity with vivid colors.

Other Physical Characteristics

Body and fin size are the main indicators of male and female Bettas, but there are other physical differences. Males typically have a uniform body color, with color changes occurring mostly in their fins and tails. In contrast, females tend to have patterned bodies more frequently (3).

There’s an exception to this rule: Some Bettas have been bred to encourage a multicolored pattern, so the typical uniform body coloration seen in males doesn’t always apply. For instance, Marbled Bettas, Koi Bettas, and Dragon Bettas may appear multicolored regardless of sex.

Egg Spot (Ovipositor)

Mature female Bettas have an egg spot, also known as an ovipositor, which is the organ used to lay fertilized eggs. The egg spot is located between the ventral and anal fins and appears as a small white dot, although it can be difficult to spot. Taking a picture and zooming in can make it easier to see.

However, some male Bettas may have a false ovipositor, particularly during adolescence. In the wild, this helps protect them from other male Bettas who may view them as a threat. As male Bettas mature, they usually lose the false ovipositor, but in some cases, it can remain throughout their life.

Beard

Male Bettas have a protruding membrane under their gill cover called the opercular membrane, which sticks out and looks like a beard. Females also have this, but it’s not as noticeable as it’s in males.

When female Bettas show off their gills, their “beard” can be seen. Males can often be seen with their beards even when they’re not showing off their gills.

Behavioral Differences

In addition to physical differences, there are also behavioral differences to note between male and female Bettas.

Aggression

Male Bettas are more aggressive than females. They display a wider range of aggressive behaviors and do so more forcefully, that’s why they are known as Siamese fighting fish. Males tend to flare their gills and spread their fins more often than females, which makes them look larger and more threatening. Male Bettas are also more likely to nip at other fish or ram into them.

Female Bettas have been observed to display similar aggressive behavior to males in certain situations, such as when reacting to their own reflection in a mirror (4, 5).

However, using the “mirror test” (holding a mirror to the tank to observe the Betta’s response) is not always a reliable indicator of sex, as female Bettas can also flare and spread their fins in response to their reflection.

Reasons for Aggression

Male Bettas are well-known for being territorial and competitive, leading to increased hostility towards other males, females, and other tankmates. Aggressive behavior in males can be triggered by any perceived threat, such as the presence of other Bettas.

During feeding time, Bettas can become more aggressive if they feel their food source is threatened, and males can become more aggressive during bubble nest building and after breeding, sometimes attacking the female after she lays her eggs.

Tankmates are also a major trigger for aggression in both male and female Bettas. Fast-moving fish that occupy the top-of-the-water column, such as Guppies, Danios, and Tetras, can trigger their territorial impulses, and brightly colored fish can appear as a sexual threat to male Bettas.

Territorialism

Male Bettas tend to be more territorial than females, leading to aggressive behavior when defending their territory from tank mates. Even during tank cleaning, Betta fish may feel threatened and it’s important to avoid disturbing them as much as possible when removing decorations and scrubbing algae.

Due to their higher disposition to territorialism, male Bettas exhibit some behavioral differences. They tend to stay in one place to defend their territory, while females are more active and swim around the tank more. This may make male Bettas appear inactive, but in fact, they are actively defending their hideouts.

Mating Behavior

Male and female Bettas have distinct roles in mating and reproduction. Their behavior differs during courtship and spawning, as well as when they are sexually mature and ready to breed, whether or not a partner is present.

Breeding Bars

Female Bettas develop “breeding stripes” consisting of 5-6 lightly colored vertical bands across their body when they’re ready to breed. However, don’t mistake them for “stress stripes” or “fear stripes” which are more intense and appear horizontally across the body, and can be seen in both male and female Bettas. The presence of male Betta isn’t necessary for the development of these stripes.

Bubble Nest Building

Male Bettas are known for building bubble nests, when they are sexually mature and ready to breed, either in response to the presence of a female Betta or on their own. Male Bettas are responsible for caring for the eggs and fry after spawning, so building a bubble nest is an important part of their reproductive behavior.

In captivity, female Bettas have also been observed constructing bubble nests even in the absence of males. It’s also worth noting that bubble nests can form naturally as a result of debris collecting in bubbles created by Betta fish as they breathe on the surface of the water.

Courtship Rituals

During the breeding process, male and female Bettas engage in an elaborate courtship ritual. The female develops breeding bars and the male will build a bubble nest or has already done so. The male performs a twisting and turning mating dance, flaring and fanning his fins to attract and impress the female. He may also chase the female around the tank, which is a natural part of the mating ritual and not an act of aggression.

Reproduction

During reproduction, male Bettas fertilize the eggs of the female. This happens through a spawning embrace, in which the male flips the female upside down and wraps his body around her midsection to bring their ventral fins together. This embrace is repeated several times, with the male releasing the female to recover in between.

After fertilization, the female Betta releases her eggs, which the male gathers and places in his bubble nest. The male Betta takes care of the eggs until they hatch, while the female’s involvement in reproduction ends in most cases, once the eggs are released.

Housing Differences

Betta fish, regardless of gender, need a suitable environment to thrive. Let’s learn more about the recommended tank size and setup for them.

Tank Size and Setup

Whether male or female, Bettas have the same requirements when it comes to tank size. While they can survive in a 3-gallon tank, they will be happier and healthier in a larger tank, such as a 5 to 10-gallon tank.

If you plan to keep multiple female Bettas together (known as sorority), you’ll need an even larger tank to minimize aggression. Some people keep Betta fish sororities in 10-gallon tanks, but a 20 to 30-gallon tank is preferable. Since male Bettas are more territorial and less active than females, they may be able to live in a smaller tank.

Filtration and Lighting Needs

Male and female Betta fish have similar needs when it comes to maintaining a healthy environment. Proper filtration is necessary to remove waste and toxins from the water, and lighting is essential to replicate the natural day/night cycle.

Sponge filters are an excellent choice for Betta fish tanks because they don’t produce strong currents and help keep the water clean. It’s best to use low-wattage LED lighting to prevent overheating the tank. Setting a day/night cycle of 14 hours of light and 10 hours of dark using a timer mimics the natural environment of Bettas during the rainy season in Thailand and promotes their circadian rhythm (6).

Tank Mates

When it comes to tankmates, both male and female Bettas have different requirements and it’s important to consider their aggression and territorial behavior. It’s generally not recommended to house male and female Bettas together unless you’re creating breeding conditions. Male Bettas can become aggressive toward females, and in some cases, even kill them.

Female Betta sororities can be created, but it can be challenging due to the aggression of female Bettas. Fishkeepers have observed that female Bettas of similar colors tend to swim together in sororities (7, 8).

Introducing a male Betta into a female sorority is not recommended. Male Bettas should never be housed together as they pose an immediate territorial and sexual threat to each other, and it usually ends in violence. It’s also not recommended to house male Bettas in nearby tanks without a divider to block their view of each other.

However, with a proper selection of tankmates, both male and female Bettas can coexist peacefully with other fish such as Neon Tetras, Cory Catfish, and Cherry Shrimps.

Water Conditions

While Betta splendens are a good option for beginner pet owners as they are hardy, they require specific water parameters to thrive.

Temperature and pH Requirements

Betta fish, regardless of their gender, require the same optimal temperature and pH levels to thrive and stay healthy.

The ideal temperature for Betta fish is between 78°F and 82°F, and it’s important to use a heater to maintain a stable temperature as sudden changes can harm them.

Bettas can tolerate a pH level between 6.5 and 7.5, but it’s best to maintain a stable pH in the middle of this range. Tap water in the United States is often too alkaline for Betta fish, so it’s recommended to use a pH stabilizer to bring it down to an appropriate level.

Water Quality and Maintenance

Keeping your Betta’s water clean and healthy is crucial for their well-being, regardless of whether they’re male or female. It’s important to keep ammonia (NH₃), nitrite (NO₂−), and nitrate (NO₃-) levels below harmful levels. Please check the table for specific levels to maintain in your Betta’s tank.

Parameter	Optimal Conditions
Ammonia	0 PPM
Nitrite	0 PPM
Nitrate	<20 PPM

It’s important to regularly test your aquarium water using a reliable testing kit like the API Freshwater Master Testing Kit. Test for harmful concentrations of toxins such as ammonia, nitrite, and nitrate. If you find elevated levels, perform a partial water change to bring the water back to optimal conditions for your Betta fish’s health.

Feeding Differences

Feeding your Betta fish a balanced and healthy diet is important for their immune system and to prevent bloating and digestive problems. Here’s what you need to know about feeding male and female Bettas differently.

Nutritional Requirements

Male and female Bettas have similar nutritional needs as they are both carnivorous surface feeders.

In the wild, Betta fish eat insects, small crustaceans, and larvae. In captivity, a balanced and varied protein-rich diet is crucial for their health. Studies suggest that feeding your Betta bloodworms can improve spawning efficiency for both genders compared to commercial fish food (9).

Commercial Betta-specific pellets or flakes are formulated to meet your fish’s nutritional needs, but it’s important to check the packaging for the plant matter content, as it can be difficult for Bettas to digest.

Frozen and freeze-dried foods like Bloodworms, Daphnia, and Brine Shrimp can be beneficial supplements to their diet. Live food can replicate their natural diet in the wild, offering a good source of protein and mental stimulation, but should be used sparingly due to the risk of introducing bacteria and parasites to the tank.

Feeding Behavior

Feeding your Betta can be a rewarding experience for any hobbyist. Both male and female Bettas have similar feeding habits, so there’s no significant difference in how you feed them.

Bettas have small stomachs and are prone to overeating, so it’s important to provide them with small portions multiple times a day to avoid bloating and constipation.

Be sure to check the packaging of your Betta’s food to determine the recommended portion sizes. Typically, 3-4 pellets or two pieces of live, freeze-dried, or frozen food per meal should suffice. It’s important to watch your Betta closely during and after feeding for signs of bloating to ensure they are receiving the right amount of food.

Most hobbyists feed their Bettas twice a day, spaced 12 hours apart. However, recent research has shown that feeding juvenile Bettas three times a day can lead to a higher survival rate. Feeding twice a day is still better than once or four times (10).

Health Concerns

Both male and female Bettas experience similar health issues. However, there is a link between the vibrancy of their color and the health of their immune system, which is connected to carotenoids, a type of pigment found in their bodies.

Studies examining the effects of carotenoids on pigmentation and immunity have shown that Betta fish face a trade-off between the sexual display and immune response. Red Betta fish given extra carotenoids become more colorful and receive a boost to their immune system, while blue Betta fish have a stronger immune system because they don’t have to divert carotenoids to pigmentation (11, 12).

It has been observed that male fish are generally more brightly colored and rely heavily on their physical attributes to attract mates. This can lead to weaker immune systems compared to females, who have different evolutionary pressures. Red male Bettas are particularly vulnerable to weakened immunological responses.

Common Health Issues

Male and female Betta fish are susceptible to a range of health concerns, from minor issues like constipation to fatal diseases like dropsy.

• Fin rot: This is a common bacterial infection that affects Betta fish. It can cause the infected fins to turn black and become ragged.
• Parasites: Betta fish can be infected by common parasites such as Ich and Velvet.
• Swim Bladder Disease: This is a common ailment among Betta fish that often results from overfeeding.
• Constipation and bloating: Overfeeding or consuming too much plant-based food can cause digestive issues that lead to constipation and bloating in Betta fish.
• Dropsy: This is a fatal illness that occurs when fluid accumulates under a Betta fish’s scales. Unfortunately, by the time it’s apparent, it’s usually too late to save the fish.

Symptoms of Diseases and Illnesses

It’s essential to recognize the symptoms of various health issues that can affect male or female Betta fish. Identifying general symptoms of sickness in your fish is crucial to intervene before the condition worsens.

• Color changes: Most diseases and infections in Bettas can cause a change in their bright colors, making them appear muted or faded.
• Bloating: Overfeeding or inflammation from infection can cause bloating in Bettas.
• Swimming or floating issues: Buoyancy problems can be an indicator of Swim Bladder Disease in Bettas.
• White or gold spots: Parasites such as Ich and Velvet can cause the appearance of white spots or a dusty gold coating on your Betta’s scales.
• Signs of stress: Sickness can cause stress in Bettas, and some signs of stress include hiding, refusing to eat, staying at the bottom of the tank, or swimming with clamped fins. These symptoms can indicate that your Betta might be sick.

Conclusion

As you step into the world of Betta fish keeping, it’s crucial to distinguish between male and female Bettas. While male Bettas are the popular choice in pet stores due to their striking colors and long fins, don’t overlook the beauty of female Bettas.

With the help of this guide or a pet store employee, you can confidently select the ideal Betta fish for your aquarium. Bring a splash of color and vitality to your tank with the perfect Betta fish.