Brocolli nebula Grade A (King Nebula)

A tiny, high-pH despot ruling its alkaline domain with outsized aggression.

Meet the King Nebula betta— a striking, aggressive 5–6 cm African-style betta that thrives in high-pH water and rewards confident keepers with bold colour and character.

• Water conditions: The King Nebula is a hard-water, high-pH specialist that will only show its best colour and behaviour when parameters are kept stable and within the correct range. Aim for a pH of 7.8–8.6, a general hardness (GH) of 10–20 dGH and a carbonate hardness (KH) of 8–15 dKH to keep the water buffered and prevent pH crashes. Temperature should sit between 24–27°C (75–81°F) with plenty of dissolved oxygen and strong, well-oxygenated circulation. These cichlids tolerate moderate nitrate but not poor hygiene, so run robust filtration, perform weekly 30–40% water changes and test pH, KH, ammonia, nitrite and nitrate regularly. Avoid soft, acidic or rapidly fluctuating water — it stresses the fish, suppresses appetite and opens the door to disease. If your tap water is soft, use an African cichlid buffer or aragonite-based media to hold the pH steady, and always acclimatise new arrivals slowly to avoid osmotic shock.
• Tank size and setup: Although the King Nebula only reaches 5–6 cm, it is territorial and active, so a single specimen needs a tank of at least 120 litres, with 200 litres or more for a group. Build the aquascape around rocky caves, crevices and sight breaks using tufa, lava rock or slate, and use a sand or fine-gravel substrate that stays clean. Create distinct territories with multiple cave entrances, and leave open swimming space above the rockwork. Strong filtration, good surface movement and a tightly fitted lid are essential. If you keep a group, use the mbuna-style approach of slightly crowded stocking to diffuse aggression, and arrange rocks so territories are broken up rather than in one open arena.
• Suitable tank mates: The King Nebula is aggressive and territorial, so choose companions that can hold their own. The best tank mates are other robust African cichlids of similar size and temperament — mbuna-type species, peaceful-but-tough peacocks and haps in a large enough tank — along with armoured catfish such as Synodontis species and robust loaches. Avoid peaceful community fish, small tetras, guppies, bettas, long-finned or slow-moving species, and ornamental shrimp, which will be bullied or eaten. Introduce new fish in groups, rearrange rockwork when adding stock to reset territories, and keep a close eye on newcomers for the first two weeks. Never mix the King Nebula with fish small enough to fit in its mouth, and avoid combining it with other highly aggressive species in a tank that is too small to provide retreats.
• Feeding habits: The King Nebula is an omnivore with a strong herbivorous bias, and its diet has a direct impact on colour, growth and long-term health. Feed a staple of high-quality African cichlid pellets with a high spirulina content, supplemented with blanched spinach, courgette, cucumber, nori and other vegetable matter. Offer occasional frozen or live foods such as brine shrimp, mysis and daphnia as a treat, but keep high-protein foods limited — excessive protein, especially from mammal fats, is linked to Malawi bloat and digestive problems in rift-lake cichlids. Feed two to three small portions per day, only as much as the fish can clear in a couple of minutes, and include one fasting day per week. Remove uneaten food promptly to protect water quality, and never overfeed, as obesity and bloat are common in captive cichlids.
• Care and temperament: This is a confident, aggressive cichlid best suited to experienced keepers who understand territorial fish. Expect chasing, fin-nipping and cave-guarding, especially during spawning, when pairs become intensely protective of their brood. Provide plenty of caves and broken sight lines, keep a close watch on subdominant fish for stress, clamped fins, hiding or appetite loss, and be ready to rehome or separate a bullied specimen. Quarantine all new arrivals, acclimatise slowly and keep a hospital tank available. The King Nebula is a cave-spawning cichlid and may breed readily in the right setup, but breeding heightens aggression — plan ahead and avoid mixing pairs with delicate tank mates. With stable high-pH water, a correct diet, good filtration and sensible stocking, this fish is hardy and long-lived; poor water quality or an unsuitable diet quickly leads to bloat, fin damage and stress-related illness.