All fish / Lebiasinidae

Coral red pencilfish

Nannostomus mortenthaleri

Also known as coral-red pencilfish, coral red pencil fish, ruby red pencilfish, peruvian red pencilfish, red pencilfish, mortenthaler's pencilfish, nannostomus sp. coral red, ナノストムス・モルテンターレリ, コーラルレッドペンシル, 珊瑚红铅笔鱼, 红铅笔

This is a small, slim pencilfish. Males turn a vivid coral red with black horizontal bands, and females are paler with clearer stripes. Keepers prize it as one of the most colourful nano fish for planted, softwater blackwater tanks.

Care at a glance

Care level

Moderate

Temperament

Semi

Adult size

3 cm

Temperature

24 to 28 °C

pH

5 to 7

Smallest tank

54 litres

Keep as

Group of 8 or more, with several females per male

Diet

Carnivore: small live and frozen foods such as daphnia, cyclops, brine shrimp and grindal worms, plus fine flake or micro pellets

Swims

Middle of the tank

Lifespan

3 to 5 years

Water

Freshwater

Wild range

Peru: Río Nanay and Río Tigre areas of the upper Amazon basin

Breeding

It scatters eggs among fine plants or moss and gives no parental care, and the adults will eat the eggs. Breeding in a separate tank with soft, acidic water is possible, but raising the tiny fry on infusoria takes patience.

Good to know

Males squabble and display at each other, so give them plenty of plants and keep more females than males. Wild exports from Peru are limited, so prices are high, and plainer red Nannostomus species are sometimes sold under the same name.