The Hockey Stick Pencilfish is an elegant species with a unique oblique swimming posture, a perfect choice for peaceful planted community tanks.
Overview
The Hockey Stick Pencilfish (Nannostomus eques) is one of the most distinctive members of the Lebiasinidae family. This species inhabits slow-moving waters of the Amazon Basin — tributaries, flooded forests, and backwaters with dense vegetation. First described in 1876, it has since earned a devoted following among aquarium enthusiasts.
The defining feature of Nannostomus eques is its characteristic oblique swimming posture: the fish constantly holds itself at roughly a 45-degree angle with its head pointed upward. This behavior is unique among freshwater fish and makes the species instantly recognizable. In the wild, this posture helps the fish camouflage itself among stems of aquatic plants and collect tiny food particles from the water surface.
The body of Nannostomus eques is elongated and slender, reaching 3–4 cm in length. The coloration is golden-brown with a dark horizontal stripe running from the tip of the snout to the base of the tail. At night, the coloration changes noticeably: the stripe fades and dark vertical bars appear on the body — this is completely normal and should not be mistaken for a sign of illness.
Unlike its close relatives — the Dwarf Pencilfish and Coral Red Pencilfish — the Hockey Stick Pencilfish spends most of its time in the upper water layers, which is worth considering when planning your tank's stocking.
Tank Requirements
A small school of Nannostomus eques requires an aquarium of at least 50 liters. Optimal water parameters are: temperature 23–28°C, pH 5.5–7.5, and GH 5–12. In my experience, these fish do best at a pH of 6.0–6.8 and a temperature around 25°C.
The aquarium should be densely planted with live plants — tall stem plants such as Vallisneria, Cabomba, and Ludwigia work particularly well, providing the fish with a sense of security. Floating plants (Pistia, Salvinia, Riccia) will create the subdued lighting that is essential for this species' comfort. Bright light causes stress and drives the fish into hiding.
A dark substrate is recommended, as it brings out the fish's colors much more vividly. Water flow should be minimal: in nature, Nannostomus eques inhabits nearly still water. Driftwood and leaf litter (oak or Indian almond leaves) will tint the water slightly brown and help recreate conditions closer to their natural habitat.
Feeding and Diet
In the wild, the Hockey Stick Pencilfish feeds on tiny invertebrates, microscopic crustaceans, and zooplankton, collecting food primarily near the water surface. The small mouth of this fish is a key factor to consider when choosing foods.
In the aquarium, high-quality flakes and micro-granules crushed to an appropriate size work well. However, for optimal coloration and health, it is essential to offer live and frozen foods regularly: baby brine shrimp, daphnia, cyclops, and micro worms. Small live foods form the core of their natural diet, and including them noticeably improves the fish's overall condition.
I recommend feeding 2–3 times daily in small portions. Keep in mind that due to their oblique posture and unhurried nature, Hockey Stick Pencilfish can lose the competition for food to more active tank mates. Always ensure that food reaches all inhabitants of the aquarium.
Care and Maintenance
Nannostomus eques is not a particularly demanding species, but it is sensitive to sudden fluctuations in water parameters. Weekly water changes of 20–25% are essential. It is best to prepare replacement water in advance, matching its parameters to those in the aquarium.
Filtration should be gentle, without a strong current. A small sponge filter or an internal filter with adjustable flow works well. Strong currents exhaust these small fish and force them into hiding.
Test water parameters regularly — ammonia and nitrites must remain at zero, and nitrates should not exceed 20 mg/l. With proper care, the Hockey Stick Pencilfish has a lifespan of 3–5 years.
Note the nighttime color change: the appearance of vertical bars in the dark is a normal response, not a sign of stress or disease. However, if the fish appears pale during the day and loses its appetite, it is time to check water quality.
Compatibility
The Hockey Stick Pencilfish is an exceptionally peaceful species that must be kept in a group of 6–8 or more individuals. In a school, the fish behave more confidently, display natural behaviors, and show better coloration. Solitary specimens become timid and quickly lose their color.
Ideal tank mates are other peaceful, small fish that primarily occupy the middle and lower water layers. Excellent choices include Neon Tetras, Cardinal Tetras, Black Neon Tetras, Panda Corydoras, Pygmy Corydoras, and Otocinclus. An interesting combination can be achieved with other pencilfish — for example, the Dwarf Pencilfish, which occupies the middle water layers.
I do not recommend keeping Hockey Stick Pencilfish with active or aggressive species — large cichlids, barbs, or paradise fish. Even moderately active species can create too much disturbance for these delicate fish and outcompete them for food.
Breeding
Breeding Nannostomus eques in the home aquarium is challenging but achievable with proper preparation. These fish are egg scatterers and show no parental care.
For spawning, set up a separate tank of 10–15 liters with very soft, slightly acidic water (pH 5.5–6.5, GH 2–4). Raise the temperature to 26–28°C. Place fine-leaved plants (Java moss) or a spawning grid on the bottom to protect the eggs from being eaten by the parents.
Select a well-conditioned female with a rounded belly and the most brightly colored male. Introduce them to the breeding tank in the evening. Spawning typically occurs in the morning: the female deposits eggs on plant leaves and in the water column. After spawning, the parents must be removed immediately.
The eggs develop over 24–36 hours, and after 3–4 days the fry become free-swimming. First foods should be infusoria and micro worms. After about a week, you can transition to baby brine shrimp. The fry grow slowly and require stable water parameters. Lighting in the breeding tank should be kept minimal, as the eggs are light-sensitive.