Halfmoon Betta
Betta splendens
The Halfmoon Betta is the icon of modern fishkeeping. Its genetic characteristic is the tail spread at a perfect 180°, forming a magnificent semicircle. While breathtakingly beautiful, it is a morphologically handicapped fish: the huge fins act as a ballast, making swimming exhausting. It needs strictly static tanks (minimum 20 liters), with NO current, and plenty of broad-leafed plants near the surface (e.g. Anubias) to "lie down" and rest. It is a strict carnivore and the male MUST live alone.
Température de l’eau
24 - 29 °C
Valeur du pH
6 - 7.5
Type d'eau
Eau douce
Niveau dans le bac
Surface et milieu
Taille adulte
7 cm
Volume minimal du bac
>= 20 L
Groupe minimal
>= 1
GH
4 - 15 dGH
KH
2 - 7 dKH
TDS
80 - 295 ppm
Conductivité
125 - 461 uS/cm
Description de l'espèce
Geographical Origin and Habitat: Variety created in captivity through international artificial selection (between the United States and France in the 1990s). Does not exist in nature. Descended from the Betta splendens of the Southeast Asian swamps.
Taxonomy and Morphology: Halfmoon Betta. The maximum expression of fin hypertrophy. The name derives from the caudal fin which, when fully extended (flaring), forms a perfect 180-degree semicircle with straight edges.
Social Behavior: Highly aggressive towards other males. However, swimming is so compromised by the weight of the 180-degree tail that it is clumsy and very slow, becoming an easy victim of much smaller but fast fish.
Coloration and Sexual Dimorphism: Exists in every color mutation (Mustard Gas, Super Red, Copper, etc.). The male boasts the imposing 180-degree caudal fin. Females (Halfmoon Plakat or HMPK females) have short fins but also show the characteristic D-shaped opening of the caudal.
Soins, reproduction et cohabitation
Aquarium Setup: 20-30 liters (5-8 gallons) tank dedicated to the single specimen. Mandatory ZERO water flow and no sharp or rough decor (like lava rocks). Needs broad-leaved plants (Anubias) to be able to lean near the surface and breathe effortlessly.
Diet and Feeding: Insectivorous carnivore. Because it moves with difficulty, food must float for a long time. Feed it sparingly with dry pellets alternated with frozen bloodworms and brine shrimp to prevent lethal intestinal occlusion.
Water Quality: The water must be very warm (27°C / 81°F) and pristine. The immense halfmoon fins are prime targets for bacteria. Lack of hygiene will invariably cause fin rot in a few days.
Compatibility and Cohabitation: Strictly isolated keeping. Its slowness and its immense "veil" fins make it the perfect target for the bites of Barbs, Tetras and even small Guppies. Cohabits well only with Nerite snails.
Aquarium Breeding: Bubble nester. The reproduction of Halfmoons is complex because the males tire quickly during the embrace ritual and often fail to wrap around the female due to the tail being too stiff and cumbersome.
Risks and Diseases: Tail Biting (Self-mutilation). Frustrated by the weight of their own tail that prevents them from swimming, many Halfmoons end up eating their own caudal fin to lighten themselves, causing tremendous infections.
Origine et répartition géographiques
Variety created in captivity through international artificial selection (between the United States and France in the 1990s). Does not exist in nature. Descended from the Betta splendens of the Southeast Asian swamps.
Origine
Sélection et cultivarsAmérique du NordEurope, Méditerranée et Asie occidentaleAsie du Sud et du Sud-Est
Profil de poisson
- Tempérament
- Aggressive
- Male Halfmoon Bettas are famous for their aggressive and highly territorial temperament, particularly toward other males of their species. However, they are generally peaceful toward non-threatening, peaceful tankmates that do not resemble them in shape or color. Because of their heavy, flowy fins, they are slow swimmers and can easily become stressed or bullied by active or nippy fish. They spend much of their time slowly patrolling their territory and resting on leaves.
- Régime alimentaire
- Carnivore
- Halfmoon Bettas are obligate carnivores that require a protein-rich diet to thrive. In the aquarium, they should be fed high-quality betta pellets or flakes formulated with high protein content. Their diet should be supplemented with live or frozen foods such as bloodworms, brine shrimp, and daphnia, which mimic their natural feeding habits. It is important to avoid overfeeding, as they are prone to bloating and constipation, which can affect their swim bladder.
- Espérance de vie
- 3-5 years
- Taille adulte
- 7 cm
- Ratio des sexes
- Group
- Male Halfmoon Bettas must always be housed individually because they are highly territorial and will fight other males to the death. While females can sometimes be kept in groups known as sororities, this is an advanced practice requiring a large, heavily planted tank and careful monitoring. Keeping a male and a female together permanently is not recommended, as the male will harass the female outside of active spawning. For general hobbyists, a single male specimen per tank is the safest and most stress-free stocking option.
- Fréquence d'alimentation
- Twice daily
- It is recommended to feed a Halfmoon Betta once or twice a day in small portions that they can consume within one to two minutes. Fasting the fish for one day a week is a beneficial practice that helps clear their digestive tract and prevents bloating. Because their stomachs are roughly the size of their eye, each feeding should consist of only 2 to 4 pellets or a small pinch of food. Uneaten food should be removed promptly to prevent water contamination.
- Charge biologique
- Low
- The biological load of a single Halfmoon Betta is relatively low, making them suitable for smaller aquariums of at least 5 to 10 gallons. However, because of their large, fragile fins, maintaining pristine water quality is essential to prevent infections like fin rot. A gentle sponge filter or a baffled hang-on-back filter is ideal for processing waste without creating strong currents. Regular water changes of 15-20% weekly are recommended to keep nitrate levels low and ensure a healthy environment.
- Courant
- Stagnant
- Halfmoon Bettas have a strong preference for weak or almost still water flow due to their long, heavy fins, which make swimming in currents exhausting. Strong filtration currents will stress the fish, cause physical fatigue, and can even tear their delicate fins. Sponge filters or filters with adjustable flow rates are highly recommended to keep the current minimal. Baffling the output of standard filters with plants or aquarium decor is also an effective way to create a calm swimming environment.
- Risque de saut
- Yes
- The risk of a Halfmoon Betta jumping out of the aquarium is high, as they are naturally agile jumpers that can leap through very small openings. A secure, tight-fitting lid is absolutely essential to prevent fatal accidents. Additionally, a gap of at least one to two inches of air should be left between the water surface and the lid to allow them to breathe atmospheric air safely. This gap also prevents them from hitting the lid if they do attempt to jump.
- Reproduction
- Oviparous
- Reproduction in Betta splendens is a fascinating but complex process that requires a dedicated breeding tank with shallow, still water and floating plants. The male constructs a bubble nest at the surface and coaxes the female underneath it to spawn, wrapping around her in an embrace to fertilize the eggs. Once spawning is complete, the female must be removed immediately, as the male becomes highly aggressive and takes sole responsibility for guarding the nest and fry. Breeding Halfmoon Bettas is challenging and requires precise care for the fragile fry, which must be fed microscopic live foods like infusoria.
- Compatibilité et compagnons
- Solitary
- Due to their territorial nature and delicate fins, compatibility for Halfmoon Bettas is limited. They should not be kept with active fin-nippers, such as certain barbs or tetras, which will easily shred their long fins. Good tankmates include peaceful bottom-dwellers like Corydoras catfish, Kuhli loaches, and invertebrates like snails or Amano shrimp. If kept in a community tank, the aquarium should be at least 10 to 15 gallons, heavily planted, and closely monitored to ensure the Betta's safety and peace of mind.
- Niveau dans le bac
- Top/Middle
- Halfmoon Bettas primarily occupy the middle and top levels of the aquarium, where they can easily access the water surface to breathe. Because they possess a specialized labyrinth organ, they must gulp atmospheric air periodically, making surface access critical. Due to the heavy weight of their fins, they tire easily and require broad-leaved plants, floating rings, or commercial suction-cup leaves placed near the surface to rest. Ensuring that the surface is clear of dense floating plants allows them to breathe comfortably.
Modèles et paramètres scientifiques
FishBase
Fenêtre sur les données scientifiques officielles de l’espèce
FishBase v25.04Données synchronisées le : 15/06/2026
- Niveau trophique
- 3,3 ± 0,41 se
- Résilience
- Élevée (moins de 15 mois)
- Singularité phylogénétique (PD50)
- 0.5
- Relation bayésienne longueur-poids
- a = 0.01, b = 2.97
- VulnérabilitéVulnérabilité faible (10 / 100)
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