Halfmoon Betta (OHM RGG)

The OHM RGG is an aggressive, high-pH dwelling species reaching 6-7cm. A bold, powerful centrepiece for experienced aquarists seeking a challenge.

• Water Conditions: The OHM RGG demands a distinctly alkaline environment, thriving in water with a high pH range of 8.0 to 8.8. This is a species that originates from hard, mineral-rich waters, so maintaining a carbonate hardness (KH) of 10–18 dKH is essential for its long-term health. The temperature should be kept stable between 75°F and 82°F (24°C–28°C). Water that is soft or acidic will quickly stress the fish, leaving it susceptible to disease and dulling its vibrant colouration. Regular weekly water changes of 25–30% are non-negotiable, as this species produces a significant bioload and is extremely sensitive to ammonia and nitrite spikes. To help maintain those high pH levels, consider incorporating crushed coral, aragonite sand, or limestone rock as your substrate. These natural buffers will slowly dissolve and keep your pH stable without resorting to harsh chemical additives. A robust filtration system with strong water flow is recommended, but be sure to create calmer zones within the tank where the fish can retreat and rest.
• Aggressive Temperament & Behaviour: This is a highly territorial and aggressive fish, especially once it has established its domain within the aquarium. The OHM RGG is not a community fish by any stretch of the imagination. It will actively chase, nip at, and potentially kill smaller or more passive tank mates. In a confined space, it will display relentless dominance, establishing a strict hierarchy that can lead to constant harassment of subordinates. It is best to house this fish as a single specimen with no other fish, giving it the entirety of the tank as its own territory. Alternatively, if you have a very large aquarium (at least 125 litres), you can attempt to keep a small group in an overstocked, high-volume setup designed specifically to disperse aggression—a technique commonly used for African Cichlids. However, this approach requires expert-level knowledge and careful monitoring, and there is always a risk of fatal conflict.
• Suitable Tank Mates: Choosing tank mates for the OHM RGG is a delicate and often risky task. Only robust, equally aggressive, and similarly sized species that also prefer hard, alkaline water should even be considered. Large-shell-dwelling cichlids, certain Lake Tanganyika species, or other hard-water inhabitants of comparable size may survive, provided they are given ample hiding spaces and visual barriers. Avoid any slow-moving, long-finned, or docile fish at all costs—they will be relentlessly bullied. Invertebrates such as small shrimp or snails will almost certainly be hunted and consumed. For the majority of hobbyists, the safest and most ethical approach is to keep the OHM RGG in a single-species tank (a species-only biotope setup) where you avoid the stress and casualties associated with incompatible companions. If you do wish to try tank mates, introduce the OHM RGG last to a well-established community, giving the other fish time to claim territories first.
• Feeding Habits: The OHM RGG is an omnivorous and opportunistic feeder, but with a decided preference for high-protein foods. In the wild, this species would primarily hunt small crustaceans, insects, and larvae. To mirror this diet, offer a staple of high-quality, slow-sinking cichlid pellets or granules that contain a high proportion of fish meal or krill. Supplement this dry food with regular feedings of live or frozen protein sources to promote optimal health and growth. Excellent choices include brine shrimp (both adult and baby), bloodworms, daphnia, and finely chopped mysis shrimp. While they will accept frozen foods readily, live foods will trigger their natural hunting instincts, providing both physical exercise and mental stimulation that reduces aggression. Feed smaller portions two to three times daily rather than one large meal, ensuring that all food is consumed within two minutes to prevent water quality degradation. Providing a varied diet is crucial—without it, the fish may develop nutritional deficiencies that manifest as faded colouration or reduced vitality.
• Care Requirements: Proper care of the OHM RGG requires a spacious aquarium, with a minimum of 55 litres recommended for a single specimen. Aquascape generously with rockwork, caves, and crevices to provide the fish with a secure sense of territory. Driftwood and hardy plants that tolerate alkaline conditions, such as Anubias or Java Fern, can also be added to break up sightlines. Lighting should be moderate, replicating the clear, shallow waters of its natural habitat. Regular observation is key, as the fish's aggressive nature means injuries are possible if housed incorrectly. If you notice signs of stress—such as clamped fins, heavy breathing, or prolonged hiding—test your water parameters immediately and adjust accordingly. Always acclimatise the fish slowly to your tank using the drip method to reduce shock. With the right conditions, the OHM RGG will reward its keeper by displaying stunning colour and intriguing, albeit combative, behaviour.