Dwarf pencilfish

Nannostomus marginatus

Wild range: Amazon Basin (South America)

At a glance: Dwarf pencilfish care

Compiled reference information. Review the care notes and original sources below.

What temperature is listed for Dwarf pencilfish?

The compiled profile lists 22.0–28.0 °C for Dwarf pencilfish (Nannostomus marginatus). Check the original sources below for context and differing recommendations.

What tank size is listed for Dwarf pencilfish?

The profile lists a minimum tank volume of 10.0 US gallons (38.0 liters). Volume alone does not establish suitability; consider dimensions, group size and other inhabitants alongside the full care notes.

What pH is listed for Dwarf pencilfish?

The compiled profile lists a pH of 5.0–7.2. Review the cited care sources alongside the other water parameters in this profile.

Natural habitat

The Brown Pencilfish inhabits slow-moving rivers and blackwater streams in the Amazon Basin, characterized by soft, acidic water rich in tannins and dense vegetation.

Where they are found

The Dwarf Pencilfish is found primarily in Brazil, Guyana, and Suriname, reflecting its preference for the humid, tropical ecosystems of these regions. They are typically located in areas with plenty of plant life, which provides both food and hiding places from potential predators.

Aquarium care

Pencilfish thrive in well-planted tanks with gentle water flow and stable water parameters. They prefer a temperature range of 23-28°C and a pH of 6.0-7.2. Regular water changes and a balanced diet are essential for their health.

Feeding

Dwarf Pencilfish are omnivorous and preferred tiny foods. In the aquarium, they can be fed high-quality micro pellets, crushed flakes, and small frozen or live foods such as daphnia and brine shrimp. Due to their small mouths, it is important to ensure the food is appropriately sized for them.

Compatibility

Dwarf Pencilfish are peaceful and can be kept with other gentle species such as small tetras, rasboras, and dwarf shrimp. They should be avoided with larger or more aggressive fish, which may view them as prey.

Breeding

Breeding requires soft, slightly acidic water and fine-leaved plants for egg laying. It is best to separate breeding pairs after spawning, as adults may eat the eggs.

Sources

Compiled from multiple independent care sheets — not copied from a single site.