Coral red pencilfish care
Nannostomus mortenthaleri · A tributary of the Nanay River near Iquitos, Peru
Coral red pencilfish are slender fish just over an inch long, coral red over the whole body and fins with jet black stripes, among the most colorful of their kind.
- Tank size
- 10 US gal or larger
- Temperature
- 75 to 82 °F (24 to 28 °C)
- Group size
- 8 or more
- Temperament
- Peaceful
- Adult size
- 1.1 in
- pH
- 5 to 7
- Hardness (GH)
- 1 to 8 dGH
- Lifespan
- 3 to 5 years
- Diet
- Micropredator
- Care level
- Moderate
In a 10 gallon
20¼ × 10½ × 12 9/16 in outsideHow to keep coral red pencilfish
Coral red pencilfish are slender fish just over an inch long, coral red over the whole body and fins with jet black stripes, among the most colorful of their kind. Keep eight or more in a planted 10 gallon or larger tank with soft, acidic water, floating plants and a lid; males spar, but without harm.
Diet: Micropredator: baby brine shrimp, daphnia, crushed flakes, micro pellets. Fish food types compared · how often to feed.
Where they swim: Middle of the tank.
Coral red pencilfish tank mates
Share the temperature and water, and neither side eats, nips or bullies the other. Check the full group in the stocking checker.
Red neon blue-eye
1.2 in · 10+ gal · 74–82 °F
Salt-and-pepper corydoras
1 in · 10+ gal · 72–79 °F
Thai micro crab
1 in · 5+ gal · 70–82 °F
Spotted blue-eye
1 in · 10+ gal · 75–82 °F
Clown killifish
1.4 in · 5+ gal · 72–80 °F
Scarlet badis
0.8 in · 10+ gal · 72–79 °F
Marbled hatchetfish
1.5 in · 20+ gal · 75–82 °F
Medaka
1.5 in · 10+ gal · 65–82 °F
Keep apart
White cloud mountain minnow: No shared temperature: coral red pencilfish need 75 to 82 °F, white cloud mountain minnows 64 to 72 °F.
Pea puffer: Pea puffers belong in a tank of their own.
Fancy goldfish: Adult fancy goldfish eat fish under about 2 in; coral red pencilfish grow to 1.1 in.
Paradise fish: Adult paradise fish eat fish under about 1.2 in; coral red pencilfish grow to 1.1 in.
Golden wonder killifish: Adult golden wonder killifish eat fish under about 2 in; coral red pencilfish grow to 1.1 in.
Red-tail dwarf puffer: Red-tail dwarf puffers belong in a tank of their own.
What a coral red pencilfish tank needs
A tank of 10 US gallons or more (such as the 10 gallon) with a tight lid (they jump), and the equipment below.
As an Amazon Associate I earn from qualifying purchases.
Aquarium Co-Op Easy Flow Sponge Filter, Small
A sponge filter gives gentle flow and cannot pull in small fish. It runs from an air pump, with airline tubing and a check valve, all sold separately.
hygger AquaFall Aquarium Filter, S
Rated by the maker for 7–10 US gal, which covers a 10 gallon coral red pencilfish tank without being built for a far bigger one.
Aqueon QuietFlow Internal Power Filter 5–15 gal
Rated by the maker for 5–15 US gal, which covers a 10 gallon coral red pencilfish tank without being built for a far bigger one.
hygger Precise Aquarium Heater 50W
Coral red pencilfish need 75 to 82 °F; most homes run cooler, so a heater holds the temperature.
API Freshwater Master Test Kit
Tests ammonia, nitrite, nitrate and pH, the readings that matter most before and after adding coral red pencilfish.
Seachem Prime 100 mL
Removes chlorine and chloramine from tap water at every water change.
Fluval Edge Thermometer
Shows the water temperature at a glance, so you know it stays within 75 to 82 °F.
More choices, each with the reason it is in or out: Filters for a 10 gallon tank · Heaters for a 10 gallon tank. We don’t list fish food: any good brand of the foods under Diet will do. Plan the whole tank's equipment →
Common coral red pencilfish problems
- They hide and fade in bright, bare tanks; add plants and floating cover.
- They jump; use a lid.
Test the water first whenever fish look unwell: see what your readings mean, then match the symptom. For disease, a vet who treats fish can diagnose it and advise treatment.
More to compare
Sources
Name, origin and adult size checked against Wikipedia: Nannostomus mortenthaleri. Temperature, pH, hardness, group size, lifespan and minimum tank size are common hobby guidance, not figures from that article. Ranges are the range the species tolerates; aim for the middle. Minimum tank sizes are for an adult group. Drawings are our own; photo credits follow.
Photo credits
Real photographs from Wikimedia Commons, resized and cropped to fit; each is used under the license named.
- Coral red pencilfish Brian Gratwicke, CC BY 2.0, via Wikimedia Commons
- Salt-and-pepper corydoras D.W., CC0, via Wikimedia Commons
- Thai micro crab Sean Murray, CC BY-SA 2.0, via Wikimedia Commons
- Spotted blue-eye Der Regenbogenfisch, CC BY-SA 3.0 de, via Wikimedia Commons
- Clown killifish Dornenwolf, CC BY 2.0, via Wikimedia Commons
- Scarlet badis ATuin-hek, CC0, via Wikimedia Commons
- Marbled hatchetfish Sven Kullander, CC BY-SA 4.0, via Wikimedia Commons
- Medaka Seotaro, CC BY-SA 3.0, via Wikimedia Commons
- White cloud mountain minnow Petrtyl, CC BY 4.0, via Wikimedia Commons
- Pea puffer Beta Mahatvaraj, CC BY-SA 4.0, via Wikimedia Commons
- Fancy goldfish Benson Kua, CC BY-SA 2.0, via Wikimedia Commons
- Paradise fish André Karwath; edited by Muhammad, CC BY-SA 2.5, via Wikimedia Commons
- Golden wonder killifish Marrabbio2, CC BY-SA 3.0, via Wikimedia Commons
- Red-tail dwarf puffer Neale Monks (English Wikipedia), CC BY-SA 3.0, via Wikimedia Commons
- Neon tetra Holger Krisp, CC BY 3.0, via Wikimedia Commons
- Cardinal tetra CHUCAO, CC BY-SA 3.0, via Wikimedia Commons
- Black neon tetra Debivort, CC BY-SA 3.0, via Wikimedia Commons
- Green neon tetra Sascha Biedermann, CC BY-SA 2.5, via Wikimedia Commons
.jpg){kind=link}
.jpg){kind=link}
_edit.jpg){kind=link}
.jpg){kind=link}
