Blackmargin tetra

Moenkhausia nigromarginata

Also known as Nigromarginata tetra, Yellow moon kogal tetra

FreshwaterFish

Care at a glance

Temperature: 73–82°F (23–28°C)
pH: 5.5–7.0
Adult size: 2.1 in (5.3 cm)
Minimum tank: 20 gal (75 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Medium
Breeding: No record
Rarity: Rare
Origin: Upper Rio Tapajos basin, Mato Grosso, Brazil
Family: Characidae

Overview

The blackmargin tetra is a peaceful, middle-swimming schooler that should be kept in a group of at least eight to ten so the fish feel secure and display well. In a good group the black edging on the fins shows most clearly, especially against pale plants and a darker background. Pair it with other calm community fish of similar size, such as small tetras, hatchetfish, pencilfish, and corydoras, and avoid anything large or pushy. Feed a mix of quality flake or micro pellets with frozen and live foods like daphnia, bloodworm, and brine shrimp. Give a group around 75 liters or more with room to swim.

In the wild

This tetra comes from clear headwater streams of the upper Rio Tapajos basin in Mato Grosso, central Brazil. Match that with warm, soft, slightly acidic water between 23 and 28 degrees Celsius and pH 5.5 to 7.0. A sandy bottom, driftwood, some leaf litter, and planting around open swimming lanes suits it, with gentle flow, good oxygenation, and clean water from regular changes.

Good to know

Moenkhausia nigromarginata, described by Costa in 1994, is a characin of the family Characidae that grows to around 5.3 centimeters. Its name means black margin, for the dark edging on the fins, and living fish also show a blue eye and a blue sheen along the back in side light. Like most of its genus it is an egg-scattering spawner with no parental care, but there are no established aquarium breeding records.