Betta macrostoma

Betta macrostoma is a large wild betta reaching 9–10 cm, native to the forest streams of northern Borneo. The males' orange-red body, black markings on the head and black-and-white-framed fins make it one of the most striking bettas. The dark, white-ringed spot at the back of the dorsal fin is the source of its English name "spotfin." The male carries the fertilized eggs in his mouth. Because part of its natural habitat is under protection, choose captive-bred fish in the hobby.

• At least 80 liters and a large footprint for a pair.
• Cool (22–25°C), soft water (pH 5–7); it is sensitive to warm water.
• Roots, rocks, dried leaves and hiding places; dim light.
• Gentle flow and good oxygenation; the water should be clean and stable.
• It is an excellent jumper; a tight lid is essential.

Carnivorous. Frozen and live bloodworms, brine shrimp, mosquito larvae and small shrimp should be the staple; some fish accept granules over time. Feed in moderation 1–2 times a day.

Pairs are bonded to each other; males are territorial toward other males. It is generally calm toward other fish but hunts shrimp and small fish fry. It is mostly kept in a species tank.

Good companions: calm, medium-sized fish suited to cool, soft water: pencilfish, kuhli loach, calm rasboras.

Avoid: dwarf shrimp, fast and greedy species, fish that need warm water, a second male in a small aquarium.