Miniature Pencilfish - Nannostomus anduzei : Complete Fish Profile & Care Guide
Table of contents
Introduction
The Miniature Pencilfish (Nannostomus anduzei) is a distinguished freshwater species within the characin family, prized for its unique appearance and behaviour in the aquarium hobby. Its intriguing diurnal colour and distinctive swimming behaviour, coupled with a relatively straightforward care level, render it a fascinating choice for both novice and experienced aquarists seeking to add a touch of elegance and natural beauty to their aquatic ecosystems. The Miniature Pencilfish, an infrequently exported species for the aquarium trade, typically arrives as incidental bycatch alongside other species rather than through targeted, large-scale collections. As the smallest known member of its genus, fully mature individuals reach a maximum size of approximately 16 mm.
This species is recognized for its peaceful demeanour, yet its diminutive stature and shy nature limit its suitability as a conventional community aquarium inhabitant. Optimal conditions are achieved when housed either solitarily or with similarly small, non-aggressive species like Neon Tetras and Micro Rasboras. While fin-nipping may occur within its group, such behaviour seldom affects other tankmates. As a naturally sociable species with a preference for shoaling over schooling, acquiring a group of at least 8 is recommended to diffuse any minor aggressiveness and encourage bolder, more authentic behaviours.
Ideal for "nano aquariums" due to its small size, the Miniature Pencilfish thrives in environments that replicate its native habitat conditions acidic, warm, and with low water hardness. A moderately sized tank, densely planted at the periphery and back while allowing ample open swimming space in the centre, suits them well. Utilizing floating plants to dim lighting and employing a dark substrate can significantly accentuate the species' vibrant colouration.
Despite its small size, the Miniature Pencilfish exhibits a striking appearance, characterized by a golden-brown body with a metallic gold stripe along its lateral line. Its most distinctive feature includes two vivid red patches on the anal and caudal fins, adding a splash of colour and visual interest to any aquarium setup.
Miniature Pencilfish Photos
Sexual Dimorphism
Distinguishing between male and female Miniature Pencilfish is relatively uncomplicated. Males exhibit more vivid colouration near the red patches on their caudal and anal fins, a trait that becomes particularly pronounced during the breeding season. Additionally, males possess a more streamlined body shape and feature an elongated anal fin, with modifications in some surrounding musculature to facilitate mating. In contrast, females may display a more pronounced longitudinal stripe along their body, although the red patches typically appear less intense compared to those of the males.
Quick Facts
| Scientific Name | Nannostomus anduzei |
|---|---|
| Year Described | 1987 |
| Other Names | Anduzi's Pencilfish, Miniature Nannostomus |
| Kingdom | Animalia |
| Classification | Actinopterygii |
| Order | Characiformes |
| Family | Lebiasinidae |
| Genus | Nannostomus |
| Origins | Venezuela , Brazil |
| Max Size | 2 cm |
| Temperament | Peaceful |
| Aquarium Level | Middle - Top |
| Difficulty | Beginner - Intermediate |
| Shoaling | Yes |
| Best kept as | Groups 8+ |
| Diet & Feeding | Omnivore |
| Reproduction | Egg-Scatterer |
| Average Lifespan | Up to 5 Years |
Water Parameters
| Water Type | Freshwater |
|---|---|
| pH | 5.0 - 7.0 |
| GH | 2 - 10 |
| TDS | 18 – 90 |
| ℉ | 71 - 82 |
|---|---|
| ℃ | 22 - 28 |
Natural Habitat
The Miniature Pencilfish originates from specific regions within Venezuela and northern Brazil, notably the upper reaches of the Orinoco River and the Rio Ererê, which flows into the Rio Negro. This species thrives in serene, shallow waters with clear visibility, characterized by a sandy white substrate.
The environmental landscape includes aquatic vegetation, submerged roots, and a layer of leaf detritus, providing a natural and complex habitat. Notably, specimens from the Rio Ererê exhibit adaptation to a blackwater biotope, distinguished by males with elongated anal fins in comparison to those found in the Venezuelan populations, indicating subtle morphological variations influenced by their distinct habitats.
Breeding
Breeding Miniature Pencilfish presents both a challenge and an opportunity for enrichment within the aquarist community. For optimal breeding outcomes, it is advisable to establish a specialized breeding aquarium. This environment should feature subdued lighting and a soft, air-driven filtration system to recreate the serene habitat preferred by these fish. The water conditions should be maintained at soft, acidic levels (low pH), ensuring cleanliness throughout.
The breeding tank should be populated with densely arranged fine-leaved plants, offering perfect spawning sites and egg attachment points. Employing marbles, small stones, pebbles, or a mesh substrate can prove beneficial. A mesh design permits eggs to descend safely away from potential predation by adult fish.
Throughout the spawning phase, male and female Miniature Pencilfish engage in a synchronized swimming pattern. The male's gentle pressure on the female's abdomen induces egg release. The female disperses a few eggs at a time, potentially laying up to 100 eggs. These eggs may adhere to plant surfaces or settle on the substrate.
Post-spawning, it is critical to relocate the adult fish from the breeding aquarium to prevent egg consumption. The eggs of the Miniature Pencilfish typically hatch within a 36- to 72-hour timeframe, with the fry transitioning to free-swimming status approximately 3 to 4 days after hatching. Initial fry nourishment should consist of infusoria or similarly fine foods, transitioning to larger food items as they grow.
Diet & Feeding
Miniature Pencilfish exhibit omnivorous feeding habits that necessitate a varied diet to ensure their nutritional needs are met and to maintain their vibrant colouration. In their natural habitat, these fish consume a mix of small invertebrates, algae, and plant matter, demonstrating their adaptability and diverse dietary preferences.
In the aquarium setting, it is imperative to replicate this varied diet through the provision of high-quality flake food, micro pellets, and a selection of live or frozen foods such as daphnia, brine shrimp, and bloodworms. Incorporating vegetable-based foods or algae wafers can also contribute to a balanced diet, enriching their intake with essential nutrients and fibres.
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