All fish / Lebiasinidae

Dwarf Pencilfish

Nannostomus marginatus

Also known as dwarf pencil fish, marginatus pencilfish, least pencilfish, dwarf pencilfish, pencil fish, marginated pencilfish, ドワーフペンシル, ナノストムス・マルギナタス, 小铅笔鱼, 红肚铅笔

This is a small, stocky pencilfish with three dark lengthwise bands on a golden body, set off by bright red patches in the dorsal, anal and pelvic fins. It is one of the smallest pencilfish and suits planted nano or soft water community tanks where its quiet behaviour and colour can be seen up close.

Care at a glance

Care level

Moderate

Temperament

Peaceful

Adult size

3 cm

Temperature

24 to 28 °C

pH

5 to 7.5

Smallest tank

40 litres

Keep as

Group of 8 or more

Diet

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

Swims

Middle of the tank

Lifespan

3 to 5 years

Water

Freshwater

Wild range

Northern South America: Guyana, Suriname, French Guiana, Venezuela and the lower Amazon basin in Brazil, Colombia and Peru

Breeding

It scatters eggs among fine leaved plants and gives no parental care, and adults readily eat the eggs. Breeding in a small, dimly lit tank with soft, acidic water and plenty of plants or a mesh is fairly achievable, and the tiny fry need infusoria at first.

Good to know

Its small mouth and timid nature mean it does poorly alongside boisterous or large tankmates, and males may squabble mildly over territory. Similar looking species such as Nannostomus mortenthaleri are sometimes mixed up with it in the trade.