Coral Red Pencilfish (Nannostomus mortenthaleri) Care Guide

One of the most stunningly colored pencilfish, featuring vivid red stripes alternating with black bands along the body. Males are particularly vibrant and engage in colorful sparring displays.

Overview

Nannostomus mortenthaleri is a species in the family Lebiasinidae. One of the most stunningly colored pencilfish, featuring vivid red stripes alternating with black bands along the body. Males are particularly vibrant and engage in colorful sparring displays. A relatively recent aquarium introduction that quickly gained popularity among planted tank enthusiasts.

Taxonomy

Family: Lebiasinidae
Genus: Nannostomus
Scientific name: Nannostomus mortenthaleri
Other names: Red Arc Pencilfish
Origin: South America, Peru

Habitat

Endemic to the upper Río Nanay drainage near Iquitos in Peruvian Amazonia. Inhabits soft, acidic blackwater streams. Dominant males display intense coral-red colouration and defend small territories; the species was described to science only in 2001.

Tank requirements

Minimum tank volume: 40 L
Temperature: 23-28 °C
pH: 4.5-6.5
GH: 1-8 °dGH
Water flow: low
Adult size: 2.5-3 cm
Lifespan: 3-5 years
Recommended group size: ≥ 6
Difficulty: intermediate

Diet

Classified as omnivore. Recommended feeding frequency: 2x daily. In captivity, offer a varied diet appropriate to the species — quality prepared foods supplemented with frozen or live items of suitable size.

Compatibility

Temperament: peaceful
Swimming level: middle
Compatible tank mates: Ember Tetra, Corydoras, Cherry Shrimp, Otocinclus
Avoid with: Cichlids, Large Fish, Aggressive Species

Breeding

Breeding strategy: egg-scatterer
Breeding difficulty: advanced