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Male vs Female Betta – Differences and Determining Gender

Are you thinking of buying a betta fish? Are you already an owner who wants to breed from your beloved betta? If that’s you, you’ll need to know how to tell the difference between a male and female betta fish.

In this article, I tell you everything you need to know about determining betta fish gender.

Wild vs Domesticated Betta Splendens

Fancy Halfmoon Betta on Black Background

Wild betta fish look completely different from those that you see in pet stores.

Male wild bettas lack the flowing fins and brilliant array of colors that are boasted by their captive-bred relatives, being a somewhat dull, gray-green color with short, stubby fins. In wild betta fish, females look very similar to males, although they are slightly smaller.

Sexual Dimorphism

“Sexual dimorphism” is a term that’s used frequently in articles about tropical fish, including bettas.

Basically, sexual dimorphism refers to the degree of difference between males and females of the same species. The terms “weak” and “strong” are also applied to a creature’s sexual dimorphism.

Betta In the Dark

In the case of betta fish, it’s true to say that wild bettas have a weak sexual dimorphism. In other words, it’s very difficult to tell the sexes apart. However, captive-bred betta fish have strong sexual dimorphism because the male of the species is very different in looks and behavior to the female.

That’s because captive bettas are bred for their spectacular finnage and rainbow array of colors, including metallics. Wild betta fish are naturally muted in color and have short fins and tails.

Over the years, the basic betta genes of wild fish have been toyed with by enthusiasts to create the beautiful anomalies that result in the strong sexual dimorphism of today’s captive-bred bettas.

Pet Store Stocking

How you purchase your betta fish can be an indicator of the fish’s gender.

In my experience, it’s generally male betta fish that you find for sale in small pet and fish stores. That’s because the males of the species are more eye-catching with gorgeous bright colors and flowing fins. Consequently, most hobbyists want a male betta, rather than females, which are drab in comparison.

man's hand holding a glass of water with betta fish inside

You can buy female bettas too, but I’ve found that it’s usually more specialist aquarist stores that sell them.

So, if you buy a betta from a small, regular pet store, ask the assistant if the fish is male or female. If they’re experienced, the assistant should know how to tell the gender of a betta fish.

However, if in doubt, assume that the betta is male.

Physical Differences in Appearance

Female and male bettas are very different in appearance:

Color

The Types of Betta Fish: A Guide to Colors, Patterns and Tails : Three betta fish on black background.

Male Female
  • Male bettas are brightly colored
  • Male bettas do not display stripes
  • Female bettas are more subdued in color
  • Female bettas develop vertical stripes when in mating condition

 

Fins and Tail

Red Siamese Fighting Fish isolated on white

Male Female
  • Some varieties of male bettas have long, flowing finnage
  • The male’s ventral fins are longer and thicker than those of the female
  • Female bettas have short fins
  • In short-finned Placat bettas, the female’s caudal fin is shorter than that of the male

 

Body Shape

Male and Female Siamese fighting fish in front of a white background .

Male Female
  • Male bettas are slim and narrow
  • Female bettas are shorter and wider-bodied

 

Size

Juvenile male and female bettas are the same sizes.

Betta Koi Halfmoon Plakat HMPK Male or Plakat Fighting Fish Splendens On Black Background.

Male Female
  • Adult male bettas measure 2.5 to 3 inches in length
  • Adult female betta size is 2 to 2.25 inches in length

 

Egg Spot

If the fish is female, you will see a tiny white dot between the ventral and anal fins.

The white dot is the fish’s “egg spot” or ovipositor. The ovipositor is part of the female fish’s sexual anatomy and is used to deposit her eggs during spawning.

The betta’s egg spot is so tiny that it can be difficult to see. Try taking a photo of your betta from the side and then magnify the photo to see the spot.

Betta Black Samurai Halfmoon Plakat HMPK Female or Plakat Fighting Fish Splendens On Black Background.

Male Female
  • Male bettas do not have an “egg spot”
  • Mature female bettas have an “egg spot”

 

Betta Beard

Betta fish have an opercular membrane situated underneath the gill plate cover. The membrane is visible when the fish flares its gill plates, resembling a “beard.”

Cock aquarium fish in the aquarium, macro

Male Female
  • Male bettas have a large beard that can be seen even when the fish is not flaring
  • Females have a much smaller beard that is not as visible even when flaring

 

Behavioral Differences

There are some notable differences in the behavior of male and female bettas:

Flaring

beautiful of siamese fighting fish on black background

Male Female
  • Male bettas flare their gills as a display of aggression
  • Males do not adopt a head-down position when flaring
  • Females flare at other females in a sorority to indicate dominance
  • Female bettas adopt a head-down posture when flaring

 

Aggression

Betta fish, Siamese fighting fish with green plants

Male Female
  • Male bettas are highly aggressive toward other males and will fight
  • Male bettas can be aggressive toward other species that have trailing fins
  • Female bettas can be aggressive toward each other if kept in pairs
  • Female bettas are generally peaceful in a community tank

 

Bubble Nest Building

Close up male red Siamese fighting fish and bubble nest on the surface of the water.

Male Female
  • Male bettas blow bubble nests, even if there is no female in the tank
  • Female bettas very rarely create bubble nests

 

In Conclusion

Now you know how to tell the difference between female and male bettas!

In general, males have extravagant finnage and bright colors, whereas females have short fins and are less gaudy in appearance. Consequently, it’s usually male fish that you’ll find for sale in regular pet stores.

Alison Page has been an avid fish keeper for over 35 years and has owned many different species of freshwater tropical fish including bettas. Currently Alison has two large freshwater tanks. The first tank has two huge fancy goldfish who are almost ten years old and still looking as good as ever. In the other, she has a happy community of tiger barbs, green tiger barbs, corydoras catfish, platys, and mollies.

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