Hemigrammus rubrostriatus

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Hemigrammus rubrostriatus is a small Colombian characid that is still rarely offered in the aquarium trade. Its silvery body, enhanced by a red longitudinal stripe, gives it a discreet yet distinctive appearance in a planted aquarium. Like many small South American tetras, it does best in a group, with stable water and gentle filtration. This wild-collected species remains a find for attentive aquarists, particularly because of its very high rarity. Its appeal comes both from its appearance and from the opportunity to observe a fish originating from a Colombian Orinoco basin.

General species description

Hemigrammus rubrostriatus is a small schooling fish from the family Characidae, adapted to life in freshwater habitats of South America. It should preferably be kept in a sufficiently large group to encourage natural behavior and reduce nervousness. Most activity takes place in the middle levels of the aquarium, where the fish alternates between schooling movements and brief explorations of the plants. Its temperament is generally peaceful, making it suitable for a community aquarium with calm species of similar size. The species’ very high rarity explains why it is less familiar than commoner tetras. Clean, well-oxygenated and chemically stable water is more important than an elaborate layout.

Geographical origin and biotope

This species is associated with Colombia, in the Orinoco basin, particularly around the río Inírida area. It comes from tropical streams where the water is soft and often stained by organic material from the surrounding forest. The natural habitat includes vegetated banks, submerged branches and quiet or slow-flowing areas. In the aquarium, a planted layout with a few roots and moderate lighting better reproduces this setting than a very open tank. Filtration should not create excessive current. Stable temperature and pH should be prioritized, since wild fish may be more sensitive to sudden changes during acclimation.

Precise location and local name

The reference locality is associated with the río Inírida in Colombia, within the Orinoco drainage. This geographical information helps explain its water preferences and the value of a habitat rich in shelter. No widely established Colombian vernacular name is used for this species in the aquarium trade. In English, it may be described as a red-striped tetra, referring to its lateral marking, but this is descriptive rather than an official local name. In captivity, the scientific name Hemigrammus rubrostriatus therefore remains the most precise designation, especially for a very rare species that could be confused with other small tetras.

Appearance and physical characteristics

Hemigrammus rubrostriatus has a small, streamlined body that is slightly compressed from side to side, with a silvery and translucent base coloration. Its most distinctive feature is a red longitudinal stripe that contrasts with the metallic reflection of the flank. The fins are delicate and may show subtle yellowish or reddish tones depending on lighting, condition and surroundings. As with many characids, color intensity improves when the fish is well fed, kept in a group and housed in suitable water. It should not be compared with selectively bred commercial forms, which are often more strongly colored. Adult size remains modest, making it appropriate for a mature, densely planted community aquarium.

General diet

Hemigrammus rubrostriatus is an opportunistic omnivore that usually accepts appropriately sized dry foods, provided they fit its small mouth. A varied diet containing quality micro-pellets, fine frozen foods and small live prey supports condition and coloration. Mosquito larvae, daphnia and newly hatched brine shrimp may be offered in moderate portions. Meals should be small, given once or twice daily, and fully consumed quickly to protect water quality. For a wild-collected fish, gradual dietary acclimation can be helpful. It should not be regarded as an algae eater, nor should leftover food in the aquarium be relied upon to feed it.

Essential data

• Original river name: Río Inírida
• Local name used: No widely established local name; red-striped tetra as a descriptive English name
• Origin of the scientific name: A name formed from descriptive Greek and Latin roots
• Etymology of the full name: Hemigrammus approximately means half-line; rubro means red and striatus means striped
• Common/vernacular names: Red-line tetra; red-striped tetra
• Family: Characidae
• Subfamily: Stethaprioninae
• Name pronunciation: hem-ee-GRAM-mus roo-broh-stry-AH-tus
• Discovery: Dieter Zarske, 2015
• Maximum adult size: About 4 cm
• Water temperature and pH: 24 to 28 °C; pH 5.5 to 7.0
• Stream appearance and surrounding vegetation: Tropical small streams, wooded banks, dense vegetation, roots and submerged organic debris
• Typical tankmates: Hoplisoma panda, Otocinclus affinis, Hyphessobrycon columbianus, Paracheirodon axelrodi
• Temperament and behavior: Peaceful, schooling and mainly active in the middle levels
• Water depth: Shallow to moderately deep areas
• Sexual dimorphism: Females are generally rounder when carrying eggs; differences are subtle
• Bottom structure and flow: Sand, mud or plant debris; low to moderate current

In your aquarium

Keeping Hemigrammus rubrostriatus successfully depends mainly on consistency. A proper group, soft to slightly acidic water, moderate filtration and a layout containing plants or roots provide a sound foundation. Because this is a wild-collected and very rare species, acclimation should be slow and maintenance especially careful. Regular water changes, varied foods and the absence of boisterous tankmates will help preserve natural behavior. Dim lighting and a dark substrate can also emphasize its red stripe without artificially forcing coloration.