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Betta Fish: Characteristics, Diet, Facts & More [Fact Sheet]

Welcome to the fascinating world of betta fish, a popular aquarium species known for its vibrant colors and elaborate fins. Whether you’re a potential betta fish owner, a seasoned aquarist, or simply curious about this beautiful creature, this article serves as your go-to resource.

Here, we’ll delve deep into the biology, behavior, and conservation status of betta fish, answering common questions and shedding light on often-overlooked aspects of their lives.

The Betta Fish at a Glance


Superclass:Osteichthyes (Bony fish)
Species:Varies (e.g., Betta splendens for the common Siamese fighting fish)

Essential Information

Average Size:2.5-3 inches (6-8 cm)
Average Weight:0.1-0.2 ounces (3-6 grams)
Average Lifespan:2-5 years
Geographical Range:Southeast Asia (especially Thailand, Malaysia, and Indonesia)
Conservation Status:Least Concern to Critically Endangered depending on the species (IUCN Red List)

Species and Subspecies

Although the term “betta fish” is commonly used to refer to the Siamese fighting fish (Betta splendens), there are actually around 73 recognized species in the Betta genus. Some other known species include:

  • Betta imbellis: Known as the “peaceful betta,” less aggressive than B. splendens.
  • Betta smaragdina: Also called the Emerald Green Betta, native to the Mekong basin.
  • Betta mahachaiensis: A critically endangered species, native to a specific region in Thailand.

The different species and subspecies exhibit variations in color, fin shape, and aggressiveness, among other traits. For instance, while the Betta splendens are often vividly colored, species like Betta imbellis are generally more subdued in hue.

Key Differences:

  • Aggressiveness: Varies from species to species, B. splendens being among the most aggressive.
  • Color: B. splendens have been bred to create a wide range of vibrant colors, while other species are more limited in this aspect.
  • Habitat Requirements: Some species, like Betta mahachaiensis, require more specific water conditions due to their restricted natural habitats.
Blue and red male Betta fish
Betta splendens


Betta fish are renowned for their dazzling array of colors and fin shapes. Most commonly, they come in shades of red, blue, green, purple, and even white. Their fins are often large and flowing, particularly in males, where they serve as a visual spectacle during territorial disputes and mating displays.

The males usually have more vibrant colors and longer fins compared to females. Males may have fins that span up to 3 inches (7.6 cm) while females generally have shorter fins.

Males and females differ significantly in betta fish. Males are often more colorful with larger fins, while females are relatively subdued in color and have smaller fins. However, selective breeding has led to the development of more colorful and elaborative finned females.

The labyrinth organ is one of the most distinctive and fascinating features of the betta fish. This specialized respiratory structure allows them to breathe atmospheric oxygen directly. Situated just above the gills, the labyrinth acts like a biological “scuba tank,” enabling bettas to survive in low-oxygen environments that would be inhospitable to many other types of fish.

This is particularly advantageous for living in stagnant waters like rice paddies, slow-moving streams, and even puddles. The labyrinth organ is not just a survival tool; it is a crucial part of their natural behavior, as you’ll often see bettas rising to the water’s surface to take a “gulp” of air.

Habitat and Distribution

Betta fish are primarily found in the warm, freshwater environments of Southeast Asia. The geographical range extends from Thailand and Cambodia to parts of Indonesia and Malaysia.

They inhabit a variety of water bodies, including rice paddies, slow-moving streams, and swamps. The water they inhabit is often shallow and filled with vegetation. In these environments, bettas typically prefer areas with low water flow and plenty of hiding spots.

Betta imbellis
Betta imbellis


Bettas are primarily diurnal, meaning they are active during the day and sleep at night. They are largely solitary creatures, especially the males, who are territorial and will often fight other males upon encounter. This is why they are also commonly known as Siamese fighting fish.

Betta fish are solitary and territorial. Males are particularly aggressive towards each other and will establish territories that they defend vigorously. Females can be slightly more social but are best kept either alone or in a group of five or more to diffuse aggression.

Bettas communicate mainly through body language. A flaring of the gills and fins indicates aggression or readiness for combat. They also make use of their colors for signaling. During mating, male bettas build bubble nests on the water surface and use visual displays to attract females.

Other Points:

  • Some betta species are capable of breathing atmospheric oxygen in addition to extracting oxygen through gills, thanks to a specialized organ called the labyrinth that we mentioned earlier.
  • Bettas are also known to jump out of the water, either to catch prey or switch to a more favorable location, making a lid essential for any betta aquarium.

Diet and Feeding Behavior

Bettas are primarily carnivorous and thrive on a diet rich in protein. In the wild, their diet consists mostly of insects and small crustaceans. They have a unique “gulp” feeding method, in which they swiftly rise to the water’s surface to catch their prey. In captivity, bettas often eat specially formulated betta pellets, frozen or live brine shrimp, and occasionally bloodworms.

In their natural habitat, bettas employ an ambush style of hunting, lurking among plant life to surprise their prey. Their ability to hover with precision allows them to execute quick dashes to seize small aquatic creatures. In captivity, they display similar quick movements to catch food particles that float on the water’s surface.


Bettas face a range of natural predators, depending on their geographical location and habitat. Larger fish, birds, and amphibians are the primary threats.

In the early life stages, betta fry are vulnerable to predation by insects and other small aquatic creatures.

Betta splendens
Betta splendens

Reproduction and Life Cycle

The breeding process of betta fish is fascinating and involves elaborate rituals. Males perform mating dances and construct bubble nests made of air and saliva on the water surface. Once a female is attracted, the male wraps around her in a mating embrace, during which eggs are fertilized.

The female releases the eggs, which the male then scoops up in his mouth and places in the bubble nest. Eggs usually hatch within 24-48 hours depending on water temperature.

A single spawn can produce anywhere from 30 to several hundred eggs. Once the eggs are in the bubble nest, the male takes over the duty of guarding them. He keeps watching, repairing the bubble nest as needed and keeping potential predators at bay. Once the fry are hatched, they remain in the nest for a few more days before they are able to swim freely.

Conservation and Threats

While bettas are not listed as endangered, their popularity in the pet trade has led to concerns about their wild populations. Depending on the species, their conservation status ranges from “Least Concern” to “Critically Endangered”.

The primary threats to betta fish include habitat loss due to agriculture and human settlement, as well as water pollution. Climate change could potentially impact their natural habitats in the future. Some species can be found in very small regions, which makes them very vulnerable.

Conservation programs are generally focused on habitat restoration and public awareness. Additionally, captive breeding programs exist to reduce the strain on wild populations.

Fun Facts

  1. Male bettas are known for their vibrant colors, which are actually a result of genetic mutations; wild bettas are generally more subdued in color.
  2. Bettas can remember their human caregivers and are known to interact with them, often swimming up to the glass to “greet” them.
  3. They are also known for their aggressiveness, earning them the nickname “Siamese Fighting Fish.”
  4. Despite their fighting reputation, bettas are quite intelligent and can be trained to perform simple tricks.
  5. Some betta fish have been known to live up to 9 years in captivity, although the average lifespan is closer to 3-5 years.

Frequently Asked Questions

Why do male bettas fight each other?

Male bettas are territorial and view other males as threats to their space and potential mates. This is why they are often kept alone or with females.

Is it okay to keep bettas in a bowl without a filter?

While bettas can survive in a bowl due to their labyrinth organ, a filtered tank with a heater is much healthier for them, as it helps maintain water quality and temperature.

What should I feed my betta fish?

High-quality betta pellets are usually sufficient, but occasional treats like brine shrimp or bloodworms can offer extra nutrition and enrichment.

Why is my betta fish not eating?

Loss of appetite could be due to various factors like stress, illness, or poor water quality. If a betta refuses to eat, it’s important to consult a veterinarian specialized in fish care.

Can I keep other fish with my betta?

It’s risky to keep male bettas with other fish, especially other males, as they can be aggressive. However, some people have successfully kept bettas in community tanks with non-aggressive species, although it’s crucial to monitor the tank dynamics closely.

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