Hyphessobrycon melanostichos · Black Stripe Tetra

Overview

Small size does not make Hyphessobrycon melanostichos harmless in cramped quarters. This black-striped, red-and-blue tetra may defend territory, tear fins, and dislodge scales when space or group size is inadequate. Plan the aquarium around its social behavior rather than length alone.

Distribution & habitat

It is endemic to the Doze de Outubro River in Brazil's upper Tapajós basin. A similar fish from the Teles Pires carries a provisional cf. identification; whether it represents another species remains unresolved.

Aquarium setup

Treat the listed minimum as a lower limit. A group of twelve or more in an aquarium around 90 cm long is a better target. Small groups compete more intensely, and confined males can injure even larger companions.

Dense planting displays adult color well. Rounded stones, sand, wood, and leaves offer a more natural arrangement. Extensive moss may shelter fry from spontaneous spawning.

This is not a blackwater specialist. Do not drive pH below 5.5 in an attempt to reproduce an extremely acidic environment.

Diet & feeding

Small invertebrates, crustaceans, filamentous algae, and fallen fruit are presumed natural foods. Prepared foods are accepted, but regular live or frozen bloodworms, mosquito larvae, and small water fleas improve variety.

Behaviour & compatibility

Loose hierarchies form within the group, with males displaying and competing for females and position. Ten or more usually reduce problems, although territorial behavior can occur in larger aquaria with distinct boundaries as well.

Aggression toward other species is limited in spacious conditions, but long fins remain vulnerable. Robust, similarly sized open-water characins are useful candidates; other compatible small catfishes and nonpredatory companions require individual assessment.

Sexual dimorphism

Outside breeding condition the sexes are similar in size and appearance, although well-conditioned females may be deeper-bodied. Courting males darken, develop reddish-brown hints in the tail, and are more likely to chase conspecifics.

Breeding

An egg scatterer without parental care, it may spawn repeatedly when well conditioned. A mature moss-filled aquarium can occasionally yield surviving fry. For greater production, use a separate dim aquarium with mesh, artificial grass, marbles, fine plants, or mops to protect eggs from the adults.

Separate conditioning of the sexes often improves success. Provide slightly acidic to neutral water and gentle air-powered filtration or an airstone. Breeding advice includes both slightly cooler-water stimulation and conditions toward the warm end of the suitable range; these should not be combined into abrupt temperature swings.

Introduce one pair or one to two males with several females. Eggs are often detected the next morning. Start fry on Paramecium or very fine food around 5–50 μm, then introduce Artemia nauplii and microworms as they grow.

Notes

Compared with Hyphessobrycon sp. 'Blue Ribbon', this fish is more lightly built and streamlined, has a smaller humeral mark, and possesses red coloration absent in the other form.