Harrison's pencilfish

Care at a glance

Overview

Keep a shoal of at least 8, which brings out their confidence and gentle sparring displays. They have small mouths and are slow, deliberate feeders, so avoid fast or pushy tankmates that will beat them to food. Soft, tannin stained water and a well planted tank suit them best.

In the wild

Comes from soft, acidic forest streams and blackwater creeks in the Guianas. These are shaded, slow waters full of leaf litter, roots, and overhanging plants. The fish shoal in the middle and upper water among the tangle.

Good to know

Nannostomus harrisoni is one of the larger pencilfishes at around 6 cm, with a slender body and a dark stripe running from snout to tail. Like other pencilfish it switches to a different, blotchy pattern at night. It was once placed in the genus Poecilobrycon.

Did you know

Like all pencilfish, this species swaps its bold daytime stripe for a broken nighttime pattern, so the fish you see at lights out looks like a different animal.

Related species

• 

  Golden pencilfish

  Nannostomus beckfordi

  2.4 in (6 cm)18 gal (70 L)70–81°F (21–27°C)
• One-lined Pencilfish

  Nannostomus unifasciatus

  1.6 in (4 cm)17 gal (65 L)73–82°F (23–28°C)

• 

  Hockeystick pencilfish

  Nannostomus eques

  1.4 in (3.5 cm)15 gal (55 L)72–82°F (22–28°C)
• Twostripe pencilfish

  Nannostomus digrammus

  1.4 in (3.5 cm)12 gal (45 L)75–82°F (24–28°C)

• 

  Three-lined pencilfish

  Nannostomus trifasciatus

  1.3 in (3.3 cm)15 gal (55 L)72–82°F (22–28°C)

• 

  Barred pencilfish

  Nannostomus espei

  1.2 in (3 cm)15 gal (55 L)72–82°F (22–28°C)