Maximum size : 7 cm

Siamese Fighting Fish - Betta splendens : Complete Fish Profile & Care Guide

Table of contents


The captivating Siamese Fighting Fish (Betta Splendens) is a popular and beloved species in the world of fishkeeping. Their vibrant colours and flowing fins have captivated enthusiasts for decades, making them a staple in the aquarium hobby. Despite their aggressive nature towards other male bettas, this unique species continues to charm fish enthusiasts worldwide. It is vital to keep them separately in their own tanks to prevent aggression and ensure their happiness and well-being.

Being indigenous to tropical climates, Betta fish exhibit a preference for water temperatures within the range of 75–82 °F (24–28 °C). However, it is noteworthy that they have demonstrated a temporary capacity to endure more extreme temperatures, spanning from 56 to 95 °F (13-35 °C). In regions characterized by colder conditions, the implementation of aquarium heaters is strongly advised. This precaution arises from the fact that exposure to colder water has the potential to compromise their immune system, rendering them susceptible to specific ailments.

The pH level of the water also significantly impacts Betta's health. Ideally, a neutral pH of 7.0 is deemed optimal, although slightly elevated pH levels are tolerable within certain limits. Owing to their labyrinth organ, Betta fish can endure lower oxygen concentrations, yet their viability is compromised in inadequately maintained aquariums. Ineffectual water quality renders all tropical fish, including Betta, more prone to afflictions such as fin rot.

Consequently, despite the renowned adaptability of Betta fish to stagnant water conditions, the incorporation of a mechanical filtration system is imperative to ensure their enduring well-being and prolonged lifespan. Furthermore, the introduction of live aquatic vegetation serves a dual purpose, functioning not only as an auxiliary filtration mechanism but also as a pivotal source of enrichment for the Betta fish.

Siamese Fighting Fish, scientifically known as Betta splendens, typically attain a length ranging from approximately 6 to 8 cm. While captive specimens are renowned for their vibrant hues and impressive, elongated fins, it is noteworthy that the inherent pigmentation of these Betta individuals predominantly manifests in shades of green, brown, and grey. In their natural state, these fish present shorter fins, and their vivid colour spectrum becomes prominent primarily in situations of agitation.

Breeders have developed a wide range of colours, patterns, and fin shapes in this species, including yellow, blue, red, green, and turquoise, with various pigmentation layers. With different colour patterns such as butterfly, bi-colour, and marble, and metallic shades like gold and platinum, Bettas continue to evolve and remain a favourite in the aquarium hobby.

Siamese Fighting Fish Photos

Sexual Dimorphism

In discerning the sex of Siamese Fighting Fish, males stand out with their vibrant and striking colours and extended fins, which are often more prominent in various ornamental strains. In contrast, the female bettas are generally less colourful in appearance. The distinguishing characteristics between the two sexes are evident, making it easy for aquarists to identify and appreciate the distinct features of these captivating fish.

Featured Male
Featured Female
Female Male

Quick Facts

Scientific NameBetta splendens
Year Described1910
Other NamesBetta
OriginsCambodia , Laos , Vietnam , Thailand
Max Size7 cm
Aquarium LevelTop
DifficultyBeginner - Intermediate
Best kept as1 Male + Several Females
Diet & FeedingCarnivore
ReproductionBubble Nester
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
pH 6.5 - 7.5
GH 5 - 20
TDS 18 - 268
Ideal Temperature
76 - 80
24 - 27

The Siamese Fighting Fish has been featured on the following stamps.

Natural Habitat

The Siamese Fighting Fish is a true jewel of Southeast Asia, endemic to the Mekong basin of Cambodia, Laos, Vietnam, and the Chao Phraya River in Thailand. These captivating fish are often found in standing, sluggish waters, ranging from rice paddies and ponds to roadside ditches and swamps. Their habitats are typically shaded by a lush array of marginal vegetation, creating a picturesque scene.

 The Siamese Fighting Fish's natural environment is unique and ever-changing. During the annual monsoon season, their water conditions can shift rapidly, posing a challenge for these resilient fish. Nevertheless, they adapt quickly to the varying substrates, which can range from deep silt to sand, mud, or leaf litter. These fascinating fish prove to be an excellent study in adaptation and survival.

 Mekong River - Vietnam
Vietnam Flag


The Siamese Fighting Fish is a bubble-nesting species that requires adequate cover for successful breeding. You can use plastic tubing or incorporate floating plants to provide potential nesting sites for the female. It is essential to have a tight-fitting lid on the aquarium to maintain a warm, humid environment necessary for the proper development of the labyrinth organ of the fry. Separating the pair before spawning is unnecessary.

The male will construct the nest under a broad plant leaf, among fine-leaved surface vegetation, or in a tube and will only allow the female in the vicinity when the nest is complete. During spawning, the female will become paler in colour, and dark bars will appear on the sides. The male will wrap himself around the female as they embrace, releasing milt and a few eggs, which the female will catch between her pelvic fins and body. The male will transfer these to the nest while the female collects any loose eggs.

This process is repeated until the female has laid all her eggs. Once spawning is complete, the adults can remain in the tank. However, the female is no longer involved in the breeding process, and the male will take sole responsibility for guarding and managing the nest. The eggs will hatch within 24 to 48 hours, and the fry will remain in the nest for an additional three to four days until the yolk sac has been fully consumed.

The male will continue to collect and return any fry that fall, moving the entire nest elsewhere if he feels threatened. After the fry becomes free-swimming, they require infusoria-grade food for the first few days, followed by foods such as Artemia nauplii and microworm. Regular small water changes are recommended for optimal fry health, rather than large and infrequent changes.

Diet & feeding

The Siamese Fighting Fish is a carnivorous species that can be fed with high-quality dried foods, such as flakes and granules, once they are introduced to them. However, to maintain optimal health and colouration, it is essential to supplement their diet with small live or frozen foods, such as artemia, daphnia, and bloodworms. 

To provide a varied diet, small insects like fruit flies or pinhead crickets are also suitable food for them. However, it is crucial to ensure that the insects are well-fed with fish flakes or vegetable matter before feeding them to the fish. This practice will help to prevent any nutritional deficiencies in the Siamese Fighting Fish and promote their overall well-being.

Frequently asked questions

Bettas should be kept in tanks of at least 6 gallons to provide ample swimming space and room for enrichment.

Bettas prefer water with a pH of 6.5-7.5, a temperature of 76-80°F, and a hardness of 5-20 dH.

Bettas are carnivorous and thrive on a diet of high-quality pellets or flakes, live or frozen foods like brine shrimp, daphnia, and bloodworms.

Male Bettas are highly territorial and will fight other males, hence the name. Females are less aggressive but can also show territorial behavior.

While possible, caution is required. Avoid housing with fin-nipping species or other male Bettas. Individual temperament and tank size play a significant role.

Males typically have larger bodies, longer fins, and more vibrant colors. Females are smaller with shorter fins and less intense coloration.

With proper care, a Betta can live between 3-5 years, though some may live even longer.

They are bubble nest builders. After an elaborate courtship, the male wraps around the female, who then releases eggs for the male to fertilize. He then places the eggs into the bubble nest.

Other Bettas of interest