Three-Lined Pencilfish

Three-Lined Pencilfish (Nannostomus Trifasciatus)

The Three-Lined Pencilfish is a small, attractive freshwater species known for its slender body and striking horizontal stripes. Their colors range from olive green to golden yellow, with three distinct black lines running the length of their bodies.

At their adult size, Three-Lined Pencilfish only grows to 1.5 inches and are more aggressive than the majority of their relatives. They are fish with a shoaling nature, meaning they prefer congregating in loose groups rather than moving in unison like schooling fish. During the day, it is common for male Three-Lined Pencilfish to engage in friendly competition, which can sometimes result in nipped fins within the group. However, this behavior typically doesn't extend to other tankmates. Keeping at least 10 or more Three-Lined Pencilfish together is recommended, as larger groups help disperse aggression and encourage the fish to exhibit bolder and more natural behaviors.

Three-Lined Pencilfish are omnivores that enjoy a varied diet of high-quality flake foods, micro pellets, and live or frozen foods such as brine shrimp, daphnia, and bloodworms.

To create a comfortable habitat for Pencilfish, provide a well-planted aquarium with a dark substrate with subdued lighting to enhance their colors. Include hiding spots using driftwood, rocks, cavies, and plenty of live plants to mimic their natural environment. Pencilfish tends to swim in the middle and top regions of the tank; the addition of floating plants offers an additional sense of security and diffuse light. Pencilfish also requires a spacious aquarium, and their décor arranged to create plenty of broken lines-of-sight to reduce aggression between males.

A minimum aquarium size of 10 gallons is recommended, while an ideal community aquarium size would be 20 gallons or larger. Maintain water conditions with a pH of 5.5-7.5, hardness of 3-12 dGH, and a temperature range of 72-82°F (22-28°C).

A well-fitting tank cover is also necessary, as Three-Lined Pencilfish may jump when startled.
Introduce these fish into a mature, stable aquarium environment to ensure their health and well-being.