Betta simplex

Betta simplex is an unusual species among wild bettas: while most of its relatives live in soft, acidic peat waters, this species lives in hard, alkaline water in spring pools and swamps in Krabi's limestone terrain. It grows to about 6 cm; its brown body shines with rows of turquoise scales. The male carries the fertilized eggs in his mouth. Because its range is very small, its natural populations are vulnerable; choose captive-bred fish in the hobby.

• At least 40 liters for a pair.
• 24–27°C, pH 7–8, moderately hard to hard water; peat and soft water are not suitable for this species.
• Plants, rocks, roots and hiding places; calm water.
• A tight lid; warm air between the surface and the lid.

Carnivorous. It accepts small granules; supplement with frozen and live bloodworms, brine shrimp, daphnia and mosquito larvae. Feed small amounts 1–2 times a day.

Calm and peaceful; pairs move around together, and males display to each other. It may eat shrimplets. Because of the water parameters, tankmates should be chosen from species suited to hard water.

Good companions: small, calm fish suited to hard water: zebra danio, platy, Endler's livebearer, otocinclus.

Avoid: species that need soft, acidic water, fast and greedy schools, fin nippers, large gouramis.