Hysginon Dario

Dario hysginon is a recently described Dario species from Bangladesh and adjacent northeast India, found in slow-flowing and standing-water habitats with dense aquatic and marginal vegetation. Males are strikingly beautiful: the body is deep crimson to scarlet, crossed by several irregular dark vertical bars, with iridescent blue-green scale highlights visible at close range. Females are cryptically coloured and noticeably smaller.

Like Dario dario, this species is a micro-predator that in most cases refuses dried food entirely. It requires a nano planted aquarium with abundant vegetation, micro live foods, and minimal competition from other species. Males are territorial and should not be kept together in small tanks without sufficient visual barriers. A ratio of one male to two or three females in a dedicated 20-litre planted tank is ideal.

Cave-spawning with paternal guarding has been documented in captivity. Fry are among the smallest produced by any aquarium fish and require Paramecium or similarly fine live foods for at least the first ten days of free-swimming life.

Water: 20–26 °C, pH 6.5–7.5, soft freshwater; gentle sponge filtration only. Tank: 20 L minimum; nano planted tank with small cave structures; low flow. Feeding: Carnivore; micro live foods — baby brine shrimp, Cyclops, Grindal worm, Daphnia. Breeding: Cave-spawner; paternal guarding; fry need Paramecium initially. Compatibility: Nano only; keep with adult shrimp and other micro fish of similar temperament.