• Nannostomus beckfordi surinami: collected from Berg en Dal in Suriname.
• Nannostomus anomalus: collected in the middle Amazon close to Santarém. The upper part of the body is brownish, the lower part yellowish, and the dark lateral stripe does not reach the caudal fin. It is edged above and below by narrow silver stripes.
• Nannostomus simplex: collected in Guyana, and has a dark gray dorsal surface. It has a light band from the snout to the base of the upper caudal fin lobe, and a black band through it's snout to the base of it's lower caudal fin lobe. Except for a spot on the ventral fins, the ventral surfaces are plain.
• Nannostomus aripirangensis: collected from Arapiranga Island, close to Belém, Brazil. This is the form most commonly found in the aquarium hobby, described above.

Adult males are more intensely-colored, especially when in spawning condition, while females are noticeably rounder-bodied. Males also have a curved posterior anal fin, which is straight in the females.

As many other characins, the Nannostomus beckfordi is also an egg-scattering free spawner fish, exhibiting no parental care. Feed the adults with plenty of live and frozen foods before spawning to bring them into good condition. For breeding a small separate tank is enough with a few clumps of fine-leaved plants such as java moss where the females can depostit the eggs, or some kind of mesh with a large enough grade so the eggs can fall through it and can protect the eggs from the adults. The aquarium water should be slightly acidic or neutral (pH 6-7), soft (1-10 dGH) with a temperature of 27-28 °C. Place them to the breeding tank in the evening. They can be spawn in pairs or in a small group, and when conditions are to their liking the fish should begin to spawn on the following morning or the next day. Several batches of 1 to 5 eggs are laid among the fine-leaved plants, with a total of up to 200 eggs in some cases. The parents will eat the eggs, so after spawning they should be removed from the tank. The transparent eggs hatch in 24-36 hours, and the larvae become free-swimming after another 5-6 days. The tiny fry can be fed with very small live foods or with liquid fry food for the first days, until they are large enough to accept brine shrimp nauplii.