Medaka care
Oryzias latipes · Rice paddies and ponds of Japan, Korea and China
Medaka are hardy surface fish that handle a wide temperature range (65 to 82 °F), so they suit unheated tanks and summer patio tubs.
- Tank size
- 10 US gal or larger
- Temperature
- 65 to 82 °F (18 to 28 °C)
- Group size
- 6 or more
- Temperament
- Peaceful
- Adult size
- 1.5 in
- pH
- 6.5 to 8
- Hardness (GH)
- 5 to 18 dGH
- Lifespan
- 2 to 4 years
- Diet
- Omnivore
- Care level
- Easy
In a 10 gallon
20¼ × 10½ × 12 9/16 in outsideHow to keep medaka
Medaka are hardy surface fish that handle a wide temperature range (65 to 82 °F), so they suit unheated tanks and summer patio tubs. Keep six or more in a 10 gallon or larger tank with floating plants; they breed readily.
Diet: Omnivore: flakes, micro pellets, small live foods. Fish food types compared · how often to feed.
Where they swim: Top of the tank.
Medaka tank mates
Share the temperature and water, and neither side eats, nips or bullies the other. Check the full group in the stocking checker.
Black neon tetra
1.5 in · 10+ gal · 73–81 °F
Glowlight tetra
1.5 in · 10+ gal · 72–80 °F
White cloud mountain minnow
1.5 in · 10+ gal · 64–72 °F
African dwarf frog
1.5 in · 10+ gal · 75–82 °F
Umbrella dwarf cichlid
1.5 in · 15+ gal · 70–79 °F
Glowlight danio
1.5 in · 15+ gal · 66–75 °F
Neon tetra
1.6 in · 10+ gal · 70–79 °F
Cherry shrimp
1.6 in · 5+ gal · 65–82 °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; medaka grow to 1.5 in.
Golden wonder killifish: Adult golden wonder killifish eat fish under about 2 in; medaka grow to 1.5 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.
Axolotl: Axolotls belong in a tank of their own.
What a medaka 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. Medaka are comfortable at room temperature, so a heater is optional in a normal home.
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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 medaka 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 medaka tank without being built for a far bigger one.
API Freshwater Master Test Kit
Tests ammonia, nitrite, nitrate and pH, the readings that matter most before and after adding medaka.
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 65 to 82 °F.
More choices, each with the reason it is in or out: Filters 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 medaka problems
- Adults eat their own eggs and fry; move egg-laden plants to a separate container to raise young.
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: Oryzias latipes. 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.
- Medaka Seotaro, CC BY-SA 3.0, via Wikimedia Commons
- Black neon tetra Debivort, CC BY-SA 3.0, via Wikimedia Commons
- Glowlight tetra gonzalovalenzuela; cropped by Kyknos, CC BY 2.0, via Wikimedia Commons
- White cloud mountain minnow Petrtyl, CC BY 4.0, via Wikimedia Commons
- African dwarf frog Stuart Halliday, CC BY 3.0, via Wikimedia Commons
- Umbrella dwarf cichlid Gordon Axmann, CC BY-SA 3.0, via Wikimedia Commons
- Glowlight danio Melanochromis, Public domain, via Wikimedia Commons
- Neon tetra Holger Krisp, CC BY 3.0, via Wikimedia Commons
- Cherry shrimp TheJammingYam, CC BY-SA 3.0, 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
- 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
- Axolotl LoKiLeCh, CC BY-SA 3.0, via Wikimedia Commons
- Harlequin rasbora NasserHalaweh, CC BY-SA 4.0, via Wikimedia Commons
- Chili rasbora JoKrimmel, CC BY-SA 4.0, via Wikimedia Commons
- Celestial pearl danio Cisamarc, CC BY-SA 3.0, via Wikimedia Commons
- Zebra danio Roundish, CC0, via Wikimedia Commons
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