All fish / Lebiasinidae

Marilyn's Pencilfish

Nannostomus marilynae

Also known as marilyn's pencilfish, marilynae pencilfish, greenstripe pencilfish, nannostomus marilyni, ナノストムス・マリリナエ, 玛丽琳铅笔鱼

This is a very small, slender pencilfish with a dark band running along each side, a lighter stripe above it and red patches on the fins of males. It is calm and shy, which makes it a good choice for planted blackwater nano tanks with other small, gentle fish.

Care at a glance

Care level

Moderate

Temperament

Peaceful

Adult size

3 cm

Temperature

24 to 28 °C

pH

4.5 to 7

Smallest tank

45 litres

Keep as

Group of 8 or more

Diet

Carnivore: small live and frozen foods such as daphnia, cyclops, brine shrimp and microworms, plus fine flake

Swims

Middle of the tank

Lifespan

3 to 5 years

Water

Freshwater

Wild range

Upper Rio Negro and Orinoco basins (Brazil, Colombia, Venezuela)

Breeding

It scatters eggs among fine plants and gives no parental care, and adults will eat the eggs. Spawning in soft, acidic water is possible, but the tiny fry need infusoria first, so raising them takes care.

Good to know

Its small mouth and timid nature mean it can go hungry or get bullied when kept with boisterous tankmates. It is often mixed up with Nannostomus marginatus and other striped pencilfish.