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Three-lined pencilfish

Nannostomus trifasciatus

Also known as Three Line Pencilfish

FreshwaterFish

Three-lined pencilfish (Nannostomus trifasciatus)
Tsunamicarlos · Public domain

Care at a glance

Temperature
72–82°F
22–28°C
pH
5.5–7.0
Adult size
1.3 in
3.3 cm
Minimum tank
15 gal
55 L
Temperament
Peaceful
Social behavior
Shoaling
Swim level
Middle
Difficulty
Medium
Breeding
Egg scatterer · Medium
Rarity
Rare
Family
Lebiasinidae
Origin
South America

Overview

The three-lined pencilfish is a small, gentle shoaling fish for a quiet planted tank. It is best with a little experience.

Did you know

The three-lined pencilfish changes its look between day and night. After lights-out, its clear daytime stripes break up into a spotted or banded pattern. It can surprise you the first time you check the tank in the dark, but it is a normal resting color, not stress.

Caring for the three-lined pencilfish

Keep three-lined pencilfish in a group of at least six, and more if you can. Give them a dim tank of at least 15 gal (55 L), with plenty of plant cover, driftwood and dried leaves. Some peat or botanicals can soften and tint the water.

Keep the water soft and acidic, at 72 to 82°F (22 to 28°C) and a pH of 5.5 to 7.0. Their mouths are tiny, so feed small foods such as micro pellets and fine flake. Add little live or frozen foods such as daphnia, baby brine shrimp and microworms.

They hold in the middle and upper water and can be shy, so they show best in a calm setup. They are gentle and suit a quiet community of similar-sized fish. They scatter their eggs, and breeding them is moderately tricky.

Good to know

The three-lined pencilfish is a small pencilfish in the family Lebiasinidae. It has three dark horizontal stripes down its slender body.

In the wild

The three-lined pencilfish lives in slow blackwater streams and tributaries of the Amazon basin, in Brazil, Peru and Colombia. The water there is acidic, soft and stained brown with tannins, with leaf litter and plants everywhere.

Weekly picks

Tank mates

The three-lined pencilfish is a peaceful, shoaling species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

What size tank does a three-lined pencilfish need?

A three-lined pencilfish needs at least 15 gal (55 L). It spends most of its time in the middle.

What temperature and pH does a three-lined pencilfish need?

A three-lined pencilfish is comfortable at 72–82°F (22–28°C) with a pH of 5.5–7.0.

What does a three-lined pencilfish eat?

A three-lined pencilfish has a tiny mouth, so it needs small foods such as micro pellets and fine flake. Give it little live or frozen foods too, such as daphnia, baby brine shrimp and microworms.

How big does a three-lined pencilfish get?

An adult three-lined pencilfish reaches about 1.3 in (3.3 cm).

Does a three-lined pencilfish need a group?

Yes. A three-lined pencilfish is a shoaling species and should be kept in a group, not singly.

How does a three-lined pencilfish breed?

The three-lined pencilfish scatters its eggs. Breeding it is moderately tricky.

Related species