Betta Fish Gestation Period: How Long Are Betta Fish Pregnant?

Red Animals - Siamese Fighting Fish

Written by Kathryn Dueck

Updated: October 30, 2023

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If you want a pet with a healthy dose of flair and style, look no further than the betta fish! These small but flamboyant fish own whatever space they’re in, whether a simple fishbowl or a large tank. Because of their aggression, however, they make better companions to humans than to other fish. So what happens when they want to mate? Do they eat their own young? How long are betta fish pregnant, and how many fry do they typically have? Discover the answers to these questions below!

Types of Betta Fish

pet betta fish tanks

Bettas are small, colorful fish that belong to the


genus in the



©panpilai paipa/

Bettas are small, colorful fish belonging to the Betta genus in the Osphronemidae family. Scientists classify them as ray-finned bony fishes. The most common species of betta fish is the Siamese fighting fish. Its scientific name is Betta splendens meaning “beautiful warrior.” Next to goldfish and guppies, bettas are some of the most common aquarium pets.

Humans bred this species to be more aggressive than it normally would be in the wild, pitting bettas against each other for sport. Today, they are bred for various colors and tail patterns. Males remain more aggressive on average than females.

At least 72 other species exist within the Betta genus, including:

  • Peaceful betta (Betta imbellis)
  • Spotfin betta (Betta macrostoma)
  • Borneo fighting fish (Betta taeniata)
  • Java fighting fish (Betta picta)
  • Slim fighting fish (Betta bellica)

Betta Fish Appearance and Size

Betta fish come in various colors, patterns, and tail shapes. Males typically have brighter colors and more elaborate tail fins than females. Possible colors include white, gray, black, blue, green, red, yellow, orange, violet, gold, and turquoise. Dark blue and dark red are particularly common. These colors also come in various combinations like the Cambodian betta (pink body with red fins), bicolor betta, butterfly betta, and dragon scale betta.

Betta tails are some of the showiest in the animal kingdom. Common tail types include veiltail, crowntail, combtail, double tail, halfmoon tail, over-double tail, and delta tail. Males use their bright colors and intricate tails to attract females and intimidate males. However, in the wild, these characteristics are much more subdued, as they would attract too many predators and slow down the betta.

Adult betta fish reach between 2-3 inches in length, with 2.5 inches (6.35 cm) being the average. Male bettas tend to be slightly larger than females.

Betta Fish Diet and Predators

What Do Betta Fish Eat
Betta fish eat a mix of dried foods, flakes, and pellets. In the wild, they’ll also eat insects.

Betta fish are carnivores and therefore can’t live solely off plant matter. Wild bettas eat mostly insects, insect larvae, zooplankton, and small crustaceans. Bloodworms are a common source of nutrition that can also be fed to pet bettas. In captivity, a betta’s diet may include betta-specific fish flakes and pellets as well as various freeze-dried foods. As with any animal, too much food will cause health problems.

Being small, bettas have several predators in the wild. Possible predators include larger fish, birds like kingfishers, cats, turtles, snakes, frogs, newts, and salamanders. Male bettas may also attack and kill each other.

Betta Fish Habitat

Betta fish are native to Thailand, though they are also common in countries like Malaysia, Vietnam, Myanmar, Indonesia, Cambodia, and Laos. They live around the world and are an invasive species in some countries. They prefer the shallow waters of marshes, ponds, slow-moving streams, and rice paddies. As freshwater fish, they can’t typically survive in salt water.

Betta fish owners should keep the temperature of their fish tank between 75-80 degrees Fahrenheit. Colder water can kill betta fish by slowing their immune systems, while warmer water can shorten their lives by increasing their metabolism. Heated aquariums with calm water provide the best environments for betta fish.

Betta Fish Social Behavior

Betta fish, Siamese fighting fish with green plants

Male betta fish can be extremely aggressive toward one another.

©subin pumsom/

True to their name, Siamese fighting fish can be extremely aggressive toward other fish, especially males. This behavior is typically more prominent in domesticated males. Females may get along with each other, though their behavior should still be monitored. Male betta fish should never be kept in a tank together or with males of other species. As males are more flamboyant and therefore more popular as pets, this usually means keeping your betta fish in a solitary environment.

Male and female betta fish will typically live together peacefully. If you are open to breeding your fish, then it should be fine to keep them in the same tank.

Betta Fish Reproduction and Lifespan

Betta fish reach sexual maturity at about 3 months of age. These fish are oviparous, meaning the female gives birth to eggs which then hatch outside her body. Because they do not give birth to live young, bettas are never technically pregnant.

Male bettas build a bubble nest or foam nest in preparation for the eggs. They do this by using their labyrinth organ (an organ that acts like a lung) to blow saliva-coated bubbles in the water. Then the male and female engage in a mating dance that culminates in the female laying her eggs. Scientists call this process “spawning.”

The male fertilizes the eggs as soon as they emerge, then brings them to the bubble nest in his mouth. He tends the nest without help from the female. Betta eggs usually hatch in 1-3 days. They survive on the egg yolk until they are ready to begin seeking other food sources.

Betta fish can live to be 2-6 years of age, though the average is 3 years in captivity.

How Long Are Betta Fish Pregnant?

pet Betta fish — also known as Siamese fighting fish in aquarium

Female betta fish carry their eggs for 1-2 weeks before mating. The male fertilizes the eggs after the female releases them.


Though betta fish are never actually pregnant, they do carry their eggs around in their ovipositor for 1-2 weeks before mating. When they are ready to mate, they release the eggs into the water to be fertilized. Females have nothing to do with their young after the eggs are released, leaving the fertilization and care of the eggs to the male.

How Can You Tell If a Betta Fish is Pregnant?

It may be difficult for an inexperienced pet owner to tell if their betta fish is carrying eggs. However, there are ways to make an educated guess. Females carrying eggs will typically look bloated, often on one side of their abdomen or the other. She will also develop vertical white or pale stripes along her body. The ovipositor, right in front of her anal fins, will visibly swell and whiten.

A gravid female will also display behavioral changes. She typically becomes more interested in the male and his bubble nest. She may even destroy it if she doesn’t like the way it was built! Her lethargy will increase as the time for laying eggs approaches.

How Often Can a Betta Fish Get Pregnant?

A Siamese female fighting fish guarding her newly laid eggs amongst the bubble nest.

Male betta fish build bubble nests in preparation for the release of the eggs.


Female betta fish can release eggs every 2 weeks through her egg spot. She does not need a male to do so, though she will usually reabsorb the eggs if they remain unfertilized. Males will attempt to fertilize any eggs in the tank. They continue to care for all eggs and fry, even if new ones appear.

How Many Fry Can a Betta Fish Produce?

Betta fish typically lay between 30-100 eggs at a time, though in rare cases, they can lay up to 500. Not all the eggs will hatch, especially in the wild, where predators abound. Nevertheless, pet owners need to be aware of the potential population explosion in their tanks and how to manage it. Too many fish in one tank, especially too many males, will result in health problems and cannibalism. Unfortunately, it is common for betta fish to eat their own eggs.

When choosing your betta fish at the store, be sure to inquire about their sex. If you get a male and female together in the same tank, you may very well become the owner of dozens of new bettas!

Bonus: Can Your Betta Share a Tank With Other Fish?

Small catfish. Cory catfish. Corydoras catfish. Peppered cory catfish. Corydoras paleatus frontal closeup with blurred natural background.

Corydoras are adorable little


that can easily share a tank with bettas.

©Kristiana Berzina/

Unless your bettas are super aggressive – they can share a tank with other types of fish. A shared tank should be at least 10 – 20 gallons with lots of cover and live plants to keep the betta from feeling too territorial. Here are some suggested tank mates that can get along with a cranky betta:

  • Cory Catfish. Corydoras are cute little schooling catfish that require at least three to six to form a shoaling group. These playful fish need each other’s company to feel safe and happy. They are happy to eat leftovers on the bottom of the tank but need sinking food to ensure proper nutrition.
  • Harlequin Rasboras. These peaceful little fish won’t interfere with your bettas during mealtime and will stay out of their way as long as you provide them company. Buy at least six together for a happy tank!
  • Malaysian Trumpet Snails. Because they are most active at night – Malaysian Trumpet
    Snails stay out of the betta’s way during the day. They burrow in the substrate by day and clean your aquarium of algae by night.
  • Ember Tetras. Lively and colorful, ember tetras are a lovely addition to any large aquarium. They tend to school around the middle of the tank and eat the same food as the bettas. Their striking red-orange color can contrast with your betta for a stunning display. Like most fish in this list, tetras are happy in schools of six.

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About the Author

Kathryn Dueck is a writer at A-Z Animals where her primary focus is on wildlife, dogs, and geography. Kathryn holds a Bachelor’s Degree in Biblical and Theological Studies, which she earned in 2023. In addition to volunteering at an animal shelter, Kathryn has worked for several months as a trainee dog groomer. A resident of Manitoba, Canada, Kathryn loves playing with her dog, writing fiction, and hiking.

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