Royal Black Arrow Tetra - Inpaichthys luizae

Royal Black Arrow Tetra (Inpaichthys luizae)

The Royal Black Arrow Tetra, Inpaichthys luizae, is a rare and recently described Brazilian tetra with a sleek body, refined metallic sheen and a bold dark arrow-like stripe running along the lower flank and into the tail. Also sold as the Black Arrow Tetra or Black Arrow Royal Tetra, this small peaceful shoaling fish is an exciting choice for mature planted aquariums and specialist South American community setups. As a newer species in the hobby, it should be kept conservatively, with stable water quality, calm tank mates and a proper group of its own kind.

Common Name:
Royal Black Arrow Tetra, Black Arrow Tetra, Black Arrow Royal Tetra, Black Arrow Inpaichthys.

Scientific Name (Latin):
Inpaichthys luizae

Maximum Size:
Around 3–4 cm, with FishBase listing females up to 3.82 cm standard length and males around 3.15 cm standard length.

Water Type:
Freshwater

Origin / Natural Habitat:
Native to Brazil. Current records place the type locality in Mato Grosso State, Juara municipality, in a tributary of the Rio dos Peixes near the Rio Arinos area; the Rio dos Peixes is part of the Rio Juruena system within the Tapajós basin. Aquarium trade reports suggest it occurs in remote or difficult-access tributary habitats, likely with sandy or silty substrate, wood, submerged branches and shaded cover.

Water Parameters:
Temperature: 22–26°C
pH Range: 5.5–7.0
Hardness or Salinity: Soft to moderately soft freshwater preferred; avoid hard, alkaline conditions and sudden changes.

Temperament:
Peaceful and sociable. Royal Black Arrow Tetras should be kept in a group and housed with calm, similarly sized tank mates. They are not aggressive, but can become nervous or washed out if kept in small numbers, bright open tanks or with large, boisterous fish.

Diet:
Omnivorous micro-feeder. Offer fine flakes, micro pellets, crushed granules, frozen daphnia, cyclops, baby brineshrimp, small bloodworm and other suitably small foods. Small live or frozen foods are especially useful for conditioning, colour and natural feeding behaviour.

Minimum Tank Size:
A minimum of 60 litres is recommended for a small group, with 90 litres or more preferred for a larger shoal in a planted community aquarium. Stability and mature filtration are more important than keeping them in the smallest possible setup.

Behaviour & Activity:
A mid-water shoaling tetra that looks best in groups of at least 8–10, with larger groups preferred where space allows. It spends much of its time moving through open water near plants, wood and shaded areas. Males may show stronger contrast and display subtly when settled, while females can be slightly fuller-bodied.

Aquarium Category:
Community Fish
Suitable with peaceful South American community fish such as small tetras, pencilfish, dwarf cichlids with care, Corydoras-type catfish, Otocinclus and other calm species that enjoy similar water conditions. Avoid aggressive cichlids, large predators, fin-nippers, very boisterous barbs and fish large enough to swallow them.

Special Requirements or Care Notes:
Best kept in a mature, well-planted aquarium with gentle to moderate filtration, stable soft water, subdued lighting and plenty of cover. Wood, leaf litter, floating plants and darker substrate can help reduce stress and enhance the dark arrow stripe. As this is a rare and newly described fish, avoid mixing with similar Inpaichthys forms if breeding purity is important. Captive-bred stock is preferable where available.

Suitable for:
Intermediate fishkeepers

Availability:
Rare / specialist import or captive-bred where relevant

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.