Coral Red Pencilfish

Nannostomus mortenthaleri

Coral Red Pencilfish is a peaceful middle-to-top swimmer.

PeacefulMiddle to top swimmerBeginner – Intermediate

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

Quick facts

Adult size: ≤ 1.2" (≤ 3 cm)
Aquarium size: 16 US gal (60 L) or larger / ≥ 35.4" (≥ 90 cm) minimum length
Care level: Beginner – Intermediate
Temperament: Peaceful
Swimming zone: Middle to top swimmer
Temperature: 75–82°F (24–28°C)
pH: 4–7
GH: 1–5 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: 16 US gal (60 L) or larger / ≥ 35.4" (≥ 90 cm) minimum length. Plan the layout and stocking within that limit.

Water parameters

Suitable water: temperature 24–28 °C, pH 4–7, GH 1–5 dGH.

Temperament and compatibility

Coral Red 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, Coral Red Pencilfish should receive a varied diet rather than one repeated food type.

Provide tiny prepared foods plus frequent small live/frozen prey including Artemia nauplii.

Before adding this fish

Plan for an aquarium of 16 US gal (60 L) or larger / ≥ 35.4" (≥ 90 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: Peru.

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) Armoured Stickleback Indostomus paradoxus Similar care level Same temperament Bottom dweller Beginner – Intermediate ≤ 1.2" (≤ 3 cm) 72–81°F (22–27°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) African Butterfly Cichlid Anomalochromis thomasi Similar care level Same temperament Bottom dweller Beginner – Intermediate ≤ 3.1" (≤ 8 cm) 73–81°F (23–27°C) African Red Eyed Tetra Arnoldichthys spilopterus Similar care level Same temperament Same swimming zone Beginner – Intermediate ≤ 3.9" (≤ 10 cm) 75–81°F (24–27°C)

FAQ

How large does Coral Red Pencilfish get?

Coral Red Pencilfish reaches ≤ 1.2" (≤ 3 cm).

What aquarium size does Coral Red Pencilfish need?

Use an aquarium of at least 16 US gal (60 L) or larger / ≥ 35.4" (≥ 90 cm) minimum length.

Is Coral Red Pencilfish peaceful?

Yes. Coral Red 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 Coral Red Pencilfish?

Keep it between 24 to 28 °C.