Coral Red Pencilfish

Coral Red Pencilfish

Nannostomus mortenthaleri

Also known as: Red Arc Pencilfish

💧 Freshwater ✌️ Peaceful 🟡 Moderate 🍽️ Omnivore Schooling (6+)

Stunning pencilfish with vivid red horizontal stripes on a cream body. One of the most colorful nano fish available.

Tank Size

10 gal
minimum (20+ preferred)

Temperature

75–82°F
24–28°C

pH Range

4.5–7
water acidity

Max Size

1.2"
3.0 cm

Lifespan

5 years
typical in captivity

Swim Level

Middle
preferred zone

Care Notes

Prefers soft, acidic water. Males are territorial — provide space and sight breaks. Colors rival any reef fish.

Feeding

Micro foods, baby brine shrimp, daphnia, and crushed flakes.

Compatible Tank Mates

Neon Tetra 1.5" Cardinal Tetra 2" Rummy Nose Tetra 2" Ember Tetra 0.8" Congo Tetra 3.5" Glowlight Tetra 1.5" Harlequin Rasbora 2" Chili Rasbora 0.7" Zebra Danio 2" Bloodfin Tetra 2" Lemon Tetra 1.5" Black Neon Tetra 1.5"

Use Caution With

Black Skirt Tetra 2.5" Serpae Tetra 1.75" Celestial Pearl Danio 1" Buenos Aires Tetra 3" Silvertip Tetra 2" Colombian Tetra 2.5" Giant Danio 4" Blue Tetra 2.5" Long-Finned Serpae Tetra 1.8" Cockatoo Dwarf Cichlid 3" Firemouth Cichlid 6" Electric Blue Acara 6"

Incompatible With

White Cloud Mountain Minnow 1.5" Angelfish 6" Oscar 14" Discus 8" Jack Dempsey 10" Convict Cichlid 5" Green Terror 8" Severum 8" Blood Parrot Cichlid 8" Texas Cichlid 12" Pike Cichlid 10" Salvini Cichlid 8"

Check Compatibility

Want to check if Coral Red Pencilfish is compatible with a specific fish? Use our compatibility checker to build your complete tank.