Maximum size : 3.5 cm

Cenepa Red Pencilfish - Nannstomus sp : Complete Fish Profile & Care Guide

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The Cenepa Red Pencilfish (Nannostomus sp. Cenepa) is a captivating addition to the fishkeeping hobby, relatively recent in its recognition as a distinct species separate from the Dwarf Pencilfish. This petite and visually appealing fish exhibits an active and personable nature, making it an excellent choice for nano or well-planted aquarium setups. However, it is important to note that the Cenepa Red Pencilfish may not thrive in typical community aquariums due to its small size and somewhat timid disposition. If considering tankmates, it is advisable to select small, non-aggressive species such as smaller Tetras, Micro Rasboras, and Dwarf Barbs, as well as compatible Corydoras Catfish and amicable Plecos.

Cenepa Red Pencilfish can also serve as ideal dither fish for Apistogrammas and other Dwarf Cichlids, as they primarily inhabit the middle to upper areas of the aquarium and do not actively prey on fry. Although they are naturally sociable, these fish exhibit shoaling behaviour rather than schooling, with rival territorial males engaging in regular sparring during daylight hours. Thus, providing a spacious aquarium with carefully arranged décor to ensure ample broken lines of sight is crucial. It is recommended to keep these fish in a group of at least ten individuals, preferably more, as larger groups not only discourage aggression towards individual fish but also promote a sense of safety, leading to more natural behaviour and an enhanced visual display.

An ideal aquarium setup for Cenepa Red Pencilfish would consist of a heavily planted environment, dark substrate, and strategically placed sheltered areas to minimize skittishness and provide refuge for sub-dominant individuals. Incorporating floating plants, driftwood branches, and dried leaf litter can further enhance the natural aesthetics of the tank. Gentle filtration, such as an air-powered sponge filter, is more than sufficient to maintain water quality. It is essential to ensure stable water conditions, as these fish are sensitive to fluctuations. Therefore, introducing them to a mature and biologically stable aquarium is crucial for their well-being.

The Cenepa Red Pencilfish exhibits a slender and diminutive physique. Male individuals showcase vibrant scarlet colouration extending into their dorsal fin, with black and white borders adorning their caudal and anal fins. In contrast, the females display a more subdued appearance, with only a splash of red noticeable on the dorsal fin and operculum, reminiscent of the well-known Dwarf Pencilfish.

Cenepa Red Pencilfish Photos

Sexual Dimorphism

Distinguishing between the male and female Cenepa Red Pencilfish is a straightforward task. Adult males exhibit a slimmer physique compared to females, and their vibrant colouration is considerably more pronounced. Another method for discerning their sex is by observing their behaviour. Males frequently engage in presenting behaviours and nip at each other, displaying territorial tendencies. Conversely, females exhibit a more docile demeanour.

Quick Facts

Scientific NameNannstomus sp
Other NamesSuper Red Coral Pencilfish, Albertini Super Red Pencilfish
Max Size3.5 cm
Aquarium LevelMiddle - Top
DifficultyBeginner - Intermediate
Best kept asGroups 5+
Diet & FeedingOmnivore
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
pH 4.0 - 7.0
GH 1 - 12
TDS 18 - 90
Ideal Temperature
75 - 82
23 - 27

Natural Habitat

The stunning Cenepa Red Pencilfish is exclusively found in the Rio Amaya, a tributary of the Rio Morona, one of the primary sources of the Amazon River in Peru, South America. These fish inhabit tannin-stained, clear blackwater environments characterized by their low mineral content.


Breeding the Cenepa Red Pencilfish presents a rewarding but challenging endeavour, particularly for hobbyists who possess a moderate level of experience. To initiate the breeding process, a separate breeding tank must be established, featuring mature water with a low pH level. Ample provisions of fine-leaved plants or java moss, as well as marbles, pebbles, or small rocks placed on the tank's substrate, should be provided. Dim lighting conditions are recommended, alongside gentle air-driven filtration.

When the Pencilfish are prepared to spawn, they will exhibit synchronized swimming behaviour, with the male gently bumping the female's abdomen. This gentle contact facilitates the fertilization of the eggs by the male. The female will subsequently release a few eggs at a time, descending into the plants or substrate until her full clutch is laid. To prevent potential predation, removing the parents from the breeding tank is advisable, as they have been known to consume their own eggs given the opportunity.

Typically, the eggs will hatch within 36 to 72 hours, depending on the prevailing temperature conditions. Initially, the tiny fry will rely on their yolk sacs as a source of nutrition before becoming free-swimming approximately 3 to 4 days after hatching. Once the yolk sacs are depleted, the fry can be fed infusoria, rotifers, and powdered first foods. As they continue to grow, their diet can progress to include larger foods such as microworms and baby brine shrimp. With proper feeding, it can take around two months for the fry to reach a length of approximately 1 cm, at which point they will gradually exhibit similar colouration to that of the adult specimens.

Diet & feeding

In the home aquarium, the Cenepa Red Pencilfish will readily accept most good quality dried foods such as granules, flakes and sinking pellets. These modern food products have been developed to provide all adequate nutrition to maintain your fish's health and dietary requirements. Providing additional foodstuffs such as live, frozen, and freeze-dried meals such as bloodworm, daphnia, and tubifex once or twice a week will provide other benefits to your fish's health and well-being but is not a must for this fish. It should be noted that bloodworms should only be given as an occasional treat and should not be used as the staple diet as they are difficult for fish to digest and can potentially cause blockages. This fish is an omnivore in the wild, consuming some vegetable matter. Although most modern fish foods take this into account and include them in their products, you can still supplement your fish's diet with blanched vegetables such as spinach, broccoli, and zucchini. Ensure you do not overfeed your fish and remove any leftovers the following day.

Other Pencilfish of interest