Three Lined Pencilfish

Nannostomus trifasciatus

Three Lined Pencilfish is a peaceful middle-to-top swimmer.

PeacefulMiddle to top swimmerBeginner – Intermediate

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Need help with Three Lined Pencilfish?

Explore compatibility, care or problems using this guide and your aquarium’s conditions.

Quick facts

Adult size: ≤ 1.4" (≤ 3.6 cm)
Aquarium size: 18 US gal (68 L) or larger / ≥ 29.5" (≥ 75 cm) minimum length
Care level: Beginner – Intermediate
Temperament: Peaceful
Swimming zone: Middle to top swimmer
Temperature: 72–82°F (22–28°C)
pH: 4–7.5
GH: 1–12 dGH
Diet: Omnivore
Lifespan: up to 5 years

Care requirements

Care level: Beginner – Intermediate.

Lifespan: up to 5 years.

Aquarium size and space needs

Minimum aquarium size: 18 US gal (68 L) or larger / ≥ 29.5" (≥ 75 cm) minimum length. Plan the layout and stocking within that limit.

Water parameters

Suitable water: temperature 22–28 °C, pH 4–7.5, GH 1–12 dGH.

Temperament and compatibility

Three Lined Pencilfish is peaceful and suits calm community fish.

Swimming zone and behavior

This fish uses the middle to upper part of the aquarium, so leave enough open swimming space for movement and feeding.

Feeding

As an omnivore, Three Lined Pencilfish should receive a varied diet rather than one repeated food type.

Offer appropriately small foods and regular small live or frozen invertebrates; prepared foods can supplement.

Before adding this fish

Plan for an aquarium of 18 US gal (68 L) or larger / ≥ 29.5" (≥ 75 cm) minimum length.
Avoid aggressive or highly competitive fish.
Offer a varied diet suited to this species’ documented feeding habits.

Natural habitat and origin

Origin: Brazil, Peru, Colombia, Guyana, Bolivia.

Similar fish profiles

Use these profiles to compare fish with similar care level, size, temperature range, or swimming behavior.

Barred Pencilfish Nannostomus espei Same genus Same family Similar care level Beginner – Intermediate ≤ 1.2" (≤ 3 cm) 72–82°F (22–28°C) Adonis Tetra Lepidarchus adonis Similar care level Same temperament Same swimming zone Intermediate ≤ 1.2" (≤ 3 cm) 72–79°F (22–26°C) African Copper Ribbon Tetra Rhabdalestes septentrionalis Similar care level Same temperament Same swimming zone Beginner – Intermediate ≤ 2.7" (≤ 6.9 cm) 72–82°F (22–28°C) Black-belt Tetra Hemigrammus kuroobi Similar care level Same temperament Same swimming zone Beginner – Intermediate ≤ 2" (≤ 5 cm) 75–82°F (24–28°C) Blue Tetra Tyttocharax cochui Similar care level Same temperament Same swimming zone Beginner – Intermediate ≤ 0.8" (≤ 2 cm) 73–79°F (23–26°C) African Banded Barb Barbus fasciolatus Similar care level Same temperament Same swimming zone Beginner – Intermediate ≤ 2.4" (≤ 6 cm) 68–79°F (20–26°C)

FAQ

How large does Three Lined Pencilfish get?

Three Lined Pencilfish reaches ≤ 1.4" (≤ 3.6 cm).

What aquarium size does Three Lined Pencilfish need?

Use an aquarium of at least 18 US gal (68 L) or larger / ≥ 29.5" (≥ 75 cm) minimum length.

Is Three Lined Pencilfish peaceful?

Yes. Three Lined Pencilfish is recorded as peaceful and is best planned with calm community fish that do not harass it or dominate the feeding area.

What temperature is suitable for Three Lined Pencilfish?

Keep it between 22 to 28 °C.