Freshwater Fish

Male vs. Female Betta: Differences and Gender Determination

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 a female betta fish.

In this article, I’ll tell you everything you need to know to determine the gender of your betta fish.

Wild vs Domesticated Betta Splendens

Wild betta fish look completely different than what you see in pet stores.

Male wild bettas lack the flowing fins and bright array of colors that their captive-bred relatives boast, being a somewhat dull greenish-gray color with short, stubby fins. In wild betta fish, the females closely resemble the males, although they are slightly smaller.

sexual dimorphism

«Sexual dimorphism» is a term frequently used 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» also apply to a creature’s sexual dimorphism.

In the case of betta fish, it is true that wild bettas have weak sexual dimorphism. In other words, it is very difficult to differentiate the sexes. However, captive- bred betta fish are strongly sexually dimorphic because the male of the species is very different in appearance and behavior from the female.

That’s because captive bettas are bred for their spectacular wingbeats and variety of rainbow colors, including metallic ones. Wild betta fish are naturally dull in color and have short fins and tails.

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

pet store stocking

The way you buy your betta fish can be an indicator of the sex of the fish.

In my experience, it is usually male betta fish that are for sale in small pet and fish stores. That’s because the males of the species are more striking with beautiful bright colors and flowing fins. Consequently, most hobbyists want a male betta, rather than females, which are drab by comparison.

You can also buy female bettas, but I have found that it is usually the more specialized aquarist stores that sell them.

So, if you buy a betta fish at a regular small pet store, ask the attendant if the fish is male or female. If they are experienced, the assistant should know how to distinguish the sex of a betta fish.

However, when in doubt, assume the betta is male.

Physical differences in appearance

Male and female bettas are very different in appearance:


Male Female
  • Male bettas are brightly colored
  • Male bettas don’t show stripes.
  • Female bettas are more subdued in color
  • Female bettas develop vertical stripes when they are in mating condition

fins and tail

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

body shape

Male Female
  • Male bettas are slim and narrow
  • Female bettas are shorter and broader-bodied.


Male and female juvenile bettas are the same size.

Male Female
  • Adult male bettas are 2.5 to 3 inches long.
  • The size of the adult female betta is 2 to 2.25 inches long.

egg stain

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

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

The betta fish egg spot is so small that it can be hard to see. Try taking a photo of your betta fish from the side and then zoom in on the photo to see the spot.

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 located under the cover of the gill plate. The membrane is visible when the fish expands its gills, resembling a «beard».

Male Female
  • Male bettas have a large beard that can be seen even when the fish is not on fire.
  • Females have a much smaller beard that is not as visible even when flared out.

behavioral differences

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


Male Female
  • Male bettas flare their gills as a sign of aggression
  • Males do not adopt a head-down position when widening
  • Females address other females in a sisterhood to indicate dominance
  • Female bettas adopt a head-down posture when enflamed


Male Female
  • Male bettas are very aggressive towards other males and will fight
  • Male bettas can be aggressive towards other species that have pendulous fins.
  • Female bettas can be aggressive towards each other if kept in pairs
  • Female bettas are generally peaceful in a community tank.

Bubble Nest Building

Male Female
  • Male bettas blow bubble nests, even if there isn’t a female in the tank
  • Female bettas rarely create bubble nests.

In conclusion

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

In general, males have flamboyant fins and bright colors, while females have short fins and are less conspicuous in appearance. Consequently, these are usually male fish that you will find for sale in regular pet stores.

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