Betta or Siamese Fighting Fish

Betta splendens

"Best Choice" Pet Best Choice

Bettas, also known as Siamese Fighting Fish, are small (up to 3 inches long) rather plain-colored fish native to the Mekong River basin in Thailand and Cambodia. They feature a unique organ (the labyrinth) that enables them to breathe atmospheric oxygen and thus to live in very low-oxygen waters such as slow streams, paddies, and ditches. The name “fighting fish” refers to the aggressive behavior of territorial males.

After more than a century of captive breeding, Bettas in the pet trade are very different than their wild ancestors. Bred for beauty, pet Bettas come in a variety of bright colors and have long flowing fins (longer in males).

Did You Know?

The name “fighting fish” refers to the aggressive behavior of territorial males.

Source Sustainability Best Choice

Does the harvest for wildlife trade or captive breeding of this species harm wild populations?

Little Cause for Concern

Bettas are almost exclusively bred in captivity, and therefore the pet trade does not pose a threat to wild populations. However, wild populations may be declining due to habitat loss, so it is important to only purchase captive-bred Bettas.

PetWatch Recommendation:

Only acquire a pet that is from a reputable, USDA-licensed breeder or dealer to ensure that you are not buying an illegally wild-caught and/or imported animal.

Invasion Threat Fair Choice

Does the release or escape of this species into the wild harm the environment and/or economy?

Some Cause for Concern

There is at least one record of a breeding population of Bettas becoming established in the wild in Florida. Other, warm, frost-free areas of North America could be at risk for Betta invasions.

PetWatch Recommendation:

Always keep your Betta inside a safe and secure aquarium. Never release a pet into the wild.

Animal Welfare Best Choice

Does harvest, captive breeding, transport, or being kept as a pet harm individual animals?

Little Cause for Concern

Bettas are relatively easy to breed and keep in captivity. They do well even in small aquaria. Males are aggressive and should not be kept with other fish.  Bettas also need warm (78º–80°F), still water (fins can be damaged by vigorous currents). They are very sensitive to chlorine, so tap water should be treated with a chlorine and chloramine remover (available at pet shops) prior to use. Take care not to overfeed  because uneaten food can rapidly foul the water.

PetWatch Recommendation:

Before acquiring a Betta, be sure to research its specific care requirements. For example, Bettas typically require freeze-dried tubifex worms. Although Bettas are commonly sold in small bowls, PetWatch recommends keeping Bettas in larger aquariums with live vegetation that reaches the surface to simulate their natural environment.

Health Threat Fair Choice

Does this animal pose a health risk to native wildlife, humans, livestock and agriculture?

Some Cause for Concern

Bettas are known to carry nematode parasites and some bacteria (Mycobacteria species) that can cause disease in fish and skin infections in humans. Even healthy- looking Bettas may be infected by these bacteria. People with compromised immune systems are especially susceptible to these skin infections, commonly called “fish-handler’s disease.” Bettas can also carry Edwardsiella bacteria which can infect commercially important farmed fish such as catfish, salmon, trout, and tilapia.

PetWatch Recommendation:

Due to the potential for disease transmission to humans and other household pets, always wash your hands after handling a Betta or touching the aquarium water. Ask for proof of a clean bill of health and obtain a list of any medical treatments the fish has received.

EcoHealth Alliance works at the intersection of ecosystem, animal and human health through local conservation programs and develops global health solutions to emerging diseases.
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