More info
Datasheet
| Minimum Tank Size | 40 litres / 10.57 US gallons |
| Maximum Size | 2.5cm / 0.98inches |
| Temperature | 22°C / 71.60°F - 28°C / 82.40°F |
| Hardness | 1.01dgH / 18ppm - 10.03dgH / 179ppm |
| pH | 4.0-7.0 |
General Description
The Dwarf Pencilfish (Nannostomus Marginatus) is a popular aquarium species with a short, stubby body and a distinct color pattern of three dark lateral stripes. This species is part of the Lebiasinidae family within the order Characiformes. Males lack sexual dichromatism, and their anal fin is relatively short, not extending to the caudal fin. They exhibit a diurnal color pattern change, becoming paler at night with two oblique bars visible behind the dorsal fin.
Aquarium Setup
The Dwarf Pencilfish thrives in a heavily planted tank with a dark substrate, providing broken lines of sight and reducing skittishness. Floating plants, driftwood branches, and dried leaf litter are recommended additions to mimic their natural habitat and support microbe colonies. Stable water conditions with a pH of 4.0-7.0, hardness of 18-179ppm, and a temperature range of 22-28°C are crucial. Gentle filtration, such as an air-powered sponge filter, is suitable for this species.
Behaviour
Known for its peaceful demeanor, the Dwarf Pencilfish is best kept in groups of 10 or more to spread any aggression and encourage natural behaviors. They are gregarious and make ideal companions for similarly sized, peaceful characids, smaller catfish species, or as dither fish for dwarf cichlids like Apistogramma spp. Unlike some relatives, rival males rarely display aggression towards each other.
Feeding and Diet
In its natural habitat, the Dwarf Pencilfish is a micropredator that feeds on tiny invertebrates and zooplankton. In an aquarium, they accept dried foods but should also be offered small live or frozen fare such as Artemia nauplii and Moina. Regular meals of varied food items like grindal worms are beneficial for their health.
Reproduction & Dimorphism
Reproduction of the Dwarf Pencilfish in aquariums is achievable with proper conditioning and setup. Controlled breeding can increase fry yield, with fry needing small live or dry foods initially. Adult males exhibit less stocky build compared to females, and some males from specific regions may have modified anal fins with thickened rays.
Habitat and Distribution
Found in sluggish tributaries, small rivers, and swampy areas with dense aquatic vegetation, the Dwarf Pencilfish typically inhabits blackwater regions with minimal hardness and low pH. Its distribution spans Guyana, Suriname, the Amazon basin in Peru, Colombia, and Brazil, with various populations showcasing slight color pattern differences like yellow pigmentation or red stripes on the body.