Those jewel-colored Siamese fighting fish swimming in tiny containers at the pet store? They’re actually suffering in silence, according to new research that challenges decades of retail practice in the global ornamental fish industry.
A study published December 23 in Animal Welfare found that Betta fish (Betta splendens) kept in small jars display significantly less natural behavior and more signs of stress compared to those housed in larger, furnished tanks.
The research, led by Professor Culum Brown from Macquarie University, reveals that the common practice of keeping these popular aquarium fish in containers as small as 1.5 liters (about 0.4 gallons) is severely restricting their natural behaviors.
“Current guidelines for appropriate tank size for Betta fish are vague and more concerned with water quality than other fish welfare concerns,” says Brown, whose team conducted detailed behavioral observations of male Siamese fighting fish housed in various tank sizes.
Fish Need Room to Move
The researchers studied 13 male Siamese fighting fish across five different housing conditions, ranging from tiny 1.5-liter jars to 19.3-liter aquaria (about 5 gallons), both with and without environmental enrichment like plants and hiding spots.
What they discovered challenges the widespread retail practice of displaying Bettas in small containers. Fish kept in larger tanks were significantly more active, swimming on average 92 seconds more during observation periods compared to those in jars. They also displayed more natural behaviors like foraging.
The study found that Bettas in small containers spent more time “hovering” – a behavior the researchers identified as potentially abnormal when not associated with nest-building. The fish also engaged in stereotypic swimming patterns, repetitive behaviors similar to the pacing seen in zoo animals kept in inadequate enclosures.
“These results suggest that the small, barren jars and tanks that Siamese fighting fish are often housed in are detrimental to their welfare, and larger, furnished tanks are more optimal,” the researchers wrote in their paper.
More Than Just Space
Tank complexity proved equally important to the fish’s wellbeing. When given furnished tanks with gravel, plants and hiding spots, the Bettas spent nearly half their resting time using these features rather than remaining suspended in open water.
In barren tanks without enrichment, even large ones, the fish showed more abnormal behaviors, including hovering, stereotypic swimming, and excessive interaction with tank walls.
“These animals are sentient, and we need to improve their lives,” says Professor Brown, highlighting the growing scientific recognition that fish possess impressive memory, cognitive abilities, and the capacity to feel pain.
From Thailand to Your Living Room
Siamese fighting fish are among the world’s most popular aquarium pets. Thailand alone exports over 20 million individual Bettas annually to countries including the USA, China, Singapore, France, and Iran.
The research was conducted in Singapore, which has been the leading exporter of ornamental fish since the 1980s and where fish-keeping is a popular hobby. The findings have global implications, as the practice of keeping Bettas in small containers is common worldwide.
The research team recommends a minimum tank size of 5.6 liters (about 1.5 gallons) for displaying and selling Siamese fighting fish, with larger tanks for those kept as pets. All tanks should contain gravel, plants and refuges to allow for more natural behaviors.
Individual Personalities
Interestingly, the study also revealed that individual Bettas have distinct personalities. Some fish showed higher levels of stereotypic swimming while others rarely displayed this behavior. Some preferred resting against plants, while others used different areas of the tank.
This individuality suggests that owners should pay attention to their specific fish’s preferences to create the most suitable environment, especially regarding hiding spots and tank features.
A Call for Change
The research challenges current industry standards and pet-keeping practices, which often prioritize display aesthetics and space efficiency over animal welfare.
While numerous countries have laws governing the welfare of companion animals, fish are frequently overlooked in such regulations. Singapore’s current ‘Pet Shop Licence Conditions (5) Display and Sale of Fancy Fish’ Act states “Fishes must be kept in tanks of adequate size” but doesn’t specify what constitutes “adequate” and still permits the sale of Bettas in small jars.
The findings suggest that both regulators and consumers need to reconsider what constitutes appropriate housing for these intelligent, colorful fish that have become fixtures in homes and offices worldwide.
For current and prospective Betta owners, the message is clear: these fish need more than just a decorative bowl to thrive. Providing a larger tank with plants and hiding places isn’t just a nice extra – it’s essential for their psychological wellbeing.
As our understanding of fish cognition and welfare continues to evolve, the tiny “Betta bowls” that have been a pet store staple for decades may soon become a thing of the past – replaced by more spacious, enriched environments that better meet the needs of these remarkable fish.