Golden Pencilfish (Nannostomus sp.) in a freshwater aquarium
Varies carePeacefulMid dwellerSouth America

Golden Pencilfish

Nannostomus sp.

The Golden Pencilfish (Nannostomus sp.) is a peaceful fish that's rewarding to keep. Give it a tank of at least 70 litres (18 US gallons), water held at 70-81°F, and a pH of 6.5-7.5.

Care levelVaries
TemperamentPeaceful
Min tank size18.5 US gal
pH range6.5-7.5
Temperature70-81°F
Max size2.4 in (6.0 cm)
Captive lifespan5-10 years
SchoolingNo
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Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.

Natural distribution

South America

  • South America

Regional colours match the stocking calculator's origin map.

Golden Pencilfish Tank Setup

A tank of at least 70 litres (18 US gallons) works well. Keep the water at 70-81°F with a pH around 6.5-7.5, and set up both cover and open swimming space where they spend most of their time (Mid).

What Do Golden Pencilfish Eat?

They're not fussy eaters - feed a varied diet, rotating good-quality dry, frozen, and gel foods rather than the same thing every day, and match the food size to their mouths.

Golden Pencilfish Tank Mates

The Golden Pencilfish is peaceful, which is the first thing to weigh up when you choose tank mates. Good matches come down to the whole stocking list working together - temperature, tank size, and temperament - not any single label. Before you buy, run your full stocking list through our stocking calculator. It weighs temperament, adult size, and water needs together, which a single species page can't do on its own.

Are Golden Pencilfish Good for Beginners?

Care demand varies by line and setup. Match the care level to how often you actually test and change water.

Golden Pencilfish - frequently asked questions

What size tank do Golden Pencilfish need?

Golden Pencilfish need a tank of at least 70 litres (18 US gallons). A bigger tank is always easier to keep stable, and gives them more room to settle in and behave naturally.

What water parameters do Golden Pencilfish need?

Keep them at 70-81°F with a pH of 6.5-7.5, steady rather than chased to an exact figure. In a cycled tank, ammonia and nitrite should both read 0 ppm, with nitrate kept low through regular water changes.

What do Golden Pencilfish eat?

Golden Pencilfish are omnivores and aren't fussy eaters. Feed a varied mix of good-quality dry, frozen, and gel foods, and match the food size to their mouths. Feed small amounts once or twice a day, and remove anything they don't eat.

Are Golden Pencilfish good for beginners?

It depends on the setup. Match Golden Pencilfish to how often you actually test water and perform maintenance.

Building a community? Run the full list through the stocking calculator before you add anything else.

Fish to avoid mixing with Golden Pencilfish

These well-known species are commonly sold alongside this fish but are not recommended tank mates - verify before purchasing.

  • OscarPredator - Oscar will eat or injure smaller tank mates
  • Pea PufferPredator - Pea Puffer will eat or injure smaller tank mates
  • Betta (Male)Predator - Betta (Male) will eat or injure smaller tank mates