Ruby tetra care
Axelrodia riesei · Upper Río Meta basin, Colombia, in northern South America
Ruby tetras are tiny, deep red tetras about an inch long from soft waters of northern South America.
- Tank size
- 10 US gal or larger
- Temperature
- 72 to 80 °F (22 to 27 °C)
- Group size
- 8 or more
- Temperament
- Peaceful
- Adult size
- 1 in (standard length, without the tail)
- 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 ruby tetras
Ruby tetras are tiny, deep red tetras about an inch long from soft waters of northern South America. Keep eight or more in a mature, planted 10 gallon or larger tank with soft, slightly acidic water and floating plants to dim the light; they show their full red only once settled.
Diet: Micropredator: baby brine shrimp, frozen daphnia, crushed flakes, micro pellets. Fish food types compared · how often to feed.
Where they swim: Middle of the tank.
Ruby tetra tank mates
Share the temperature and water, and neither side eats, nips or bullies the other. Check the full group in the stocking checker.
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
Crystal red shrimp
1.2 in · 10+ gal · 62–76 °F
DrawingRed neon blue-eye
1.2 in · 10+ gal · 74–82 °F
Scarlet badis
0.8 in · 10+ gal · 72–79 °F
Clown killifish
1.4 in · 5+ gal · 72–80 °F
Marbled hatchetfish
1.5 in · 20+ gal · 75–82 °F
Keep apart
Pea puffer: Pea puffers belong in a tank of their own.
Fancy goldfish: Adult fancy goldfish eat fish under about 2 in; ruby tetras grow to 1 in.
Paradise fish: Adult paradise fish eat fish under about 1.2 in; ruby tetras grow to 1 in.
Golden wonder killifish: Adult golden wonder killifish eat fish under about 2 in; ruby tetras grow to 1 in.
Red-tail dwarf puffer: Red-tail dwarf puffers belong in a tank of their own.
Everglades pygmy sunfish: Everglades pygmy sunfish belong in a tank of their own.
What a ruby tetra tank needs
A tank of 10 US gallons or more (such as the 10 gallon) with a cover, and the equipment below.
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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 ruby tetra 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 ruby tetra tank without being built for a far bigger one.
hygger Precise Aquarium Heater 50W
Ruby tetras need 72 to 80 °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 ruby tetras.
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 72 to 80 °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 ruby tetra problems
- They stay pale and hide under bright light and in bare tanks; add floating plants and a dark substrate.
- Ordinary flakes are too large for them; crush them or feed micro foods.
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: Axelrodia riesei. 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.
- Ruby tetra Thomas Siems, CC BY-SA 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
- Crystal red shrimp DirkBlankenhaus, CC BY-SA 3.0, via Wikimedia Commons
- Scarlet badis ATuin-hek, CC0, via Wikimedia Commons
- Clown killifish Dornenwolf, CC BY 2.0, via Wikimedia Commons
- Marbled hatchetfish Sven Kullander, CC BY-SA 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
- Everglades pygmy sunfish Brian Gratwicke, CC BY 2.0, 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
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