The Betta is a vibrant labyrinth fish with luxurious fins and a strong personality, easy to care for but highly aggressive toward other males of its kind.
Overview
Betta splendens, or the Betta, is arguably the most recognizable aquarium fish in the world. This species originates from shallow waters of Southeast Asia: rice paddies, ditches, and swampy areas of Thailand, Cambodia, and Vietnam. The Betta belongs to the family Osphronemidae and possesses a labyrinth organ that allows it to breathe atmospheric air — which is why the fish can survive in water with low oxygen levels.
Thanks to decades of selective breeding, an enormous variety of forms exists: veiltail, crowntail, halfmoon, plakat, and many more. Colors range from solid to multicolored — red, blue, turquoise, white, black. Adults reach 6–8 cm and live 2–5 years. Males are significantly more colorful than females and sport luxurious long fins. Bettas have a complex temperament: males are extremely aggressive toward other males and may show territoriality toward other brightly colored fish.
Tank Requirements
The minimum tank volume is 10 liters per Betta. Contrary to a widespread myth, keeping them in cups or vases is cruel, not normal. Optimal water parameters: temperature 24–30°C, pH 6.0–7.5, hardness GH 5–15. A heater is mandatory — Bettas are heat-loving and become lethargic and disease-prone at temperatures below 22°C.
Filtration is necessary but flow must be minimal — the Betta's long fins are not designed for fighting currents. Use a sponge filter or direct the filter outlet toward the wall. Substrate should be fine sand or smooth gravel without sharp edges that could damage delicate fins. Plant the tank densely with live plants: Anubias, Java moss, and Hornwort provide shelter and a sense of security. Floating plants will dim the light and give the Betta a resting spot near the surface.
Feeding and Diet
In the wild, Betta splendens is a predator that feeds on insects, their larvae, and small invertebrates that fall onto the water surface. In the aquarium, specialized Betta pellets form the staple diet — they contain an optimal balance of protein and vitamins. Supplement with frozen bloodworms, brine shrimp, and daphnia 2–3 times per week.
Feed 1–2 times daily, offering 2–4 pellets at a time. A Betta's stomach is roughly the size of its eye — overfeeding leads to bloating and constipation, a common problem for this species. Schedule a weekly fasting day. Avoid flakes — Bettas often ignore them, and uneaten food pollutes the water.
Care and Maintenance
Weekly water changes of 20–30% are the foundation of Betta health. In small tanks (10–20 liters), changes should be more frequent — up to twice a week. Ammonia and nitrites must be strictly at zero, nitrates below 20 mg/l. In unfiltered tanks, changes need to be even more frequent.
The most common diseases are fin rot, ich (white spot disease), and velvet disease. Prevention is simple: clean warm water and absence of stress. Monitor fin condition — white edges, ragged patches, or faded coloration signal problems. Do not use sharp decorations — artificial plants with rough edges and decorative castles can tear delicate fins. Perform the "stocking test": if a decoration snags stocking fabric, it is dangerous for a Betta.
Compatibility
The cardinal rule: never house two males together. They will fight to the death — the name "Siamese Fighting Fish" exists for a reason. A single male can be kept with peaceful bottom-dwellers: Corydoras, Kuhli Loach, or snails. Small peaceful tetras — neons, rasboras — are acceptable in tanks of 40 liters or more.
Avoid keeping with brightly colored fish that have long fins — the Betta may perceive them as rivals. Also avoid fin-nippers such as barbs and certain tetras. Female Bettas are less aggressive and can be kept in small groups (5+) in a spacious tank of at least 40 liters with plenty of hiding spots — a so-called "sorority tank" — but even then hierarchical aggression is possible.
Breeding
Breeding Betta splendens is quite achievable at home (difficulty 3 out of 5) but requires preparation. Set up a spawning tank of 15–20 liters with warm water (28°C), a shallow water level (10–15 cm), and no current. The male builds a bubble nest on the water surface from air bubbles bound together with saliva.
Before spawning, condition the pair with live food for a week. Introduce the female to the male — courtship involves fin flaring, dancing, and sometimes chasing. During spawning, the male wraps around the female and eggs fall downward. The male collects them and places them in the nest. Remove the female immediately after spawning — the male aggressively guards the nest. The father tends the eggs and larvae, returning fallen fry back to the nest. After 2–3 days, the fry begin free-swimming — at this point, remove the male as well. Starter food is infusoria and microworms, followed by baby brine shrimp.