Pygmy corydoras
Corydoras pygmaeus · family Callichthyidae
The pygmy corydoras (Corydoras pygmaeus) is a peaceful, freshwater catfish that grows to about 1 inch and comes from the Madeira River basin in Brazil, with populations also in Peru and Ecuador. It's an easy-care fish that lives 3 to 5 years and does best in a group of at least 8 in a mature tank of 10 gallons or more. The most important thing to know is that it's tiny and easily intimidated, so it needs gentle tankmates and sinking food it can reach.
Edited by Marin Hale · last reviewed October 29, 2026 · How we check facts
Great for beginnersTropicalMature tank onlyNano tank OKGroups of 8+
What can live with a pygmy corydoras?
Verdicts against every species in our database, from our compatibility rules. How verdicts work
| Verdict | Species | Why | Tank |
|---|---|---|---|
| Good match | Betta fish | No problems found: water, size, fins and temperament all check out. | 10 gal+ |
| Good match | Cherry shrimp | No problems found: water, size, fins and temperament all check out. | 10 gal+ |
| Good match | Ember tetra | No problems found: water, size, fins and temperament all check out. | 10 gal+ |
| Good match | Neon tetra | No problems found: water, size, fins and temperament all check out. | 10 gal+ |
| Good match | Another pygmy corydoras | No problems found: water, size, fins and temperament all check out. | 10 gal+ |
| Maybe | Guppy | pH ranges only just overlap (7.0–7.4), so one of them will be outside its comfort zone if your water drifts. | 10 gal+ |
| Maybe | Tiger barb | Tiger barbs can harass much smaller, peaceful pygmy corydoras. | 30 gal+ |
| Maybe | Zebra nerite snail | pH ranges only just overlap (7.2–7.4), so one of them will be outside its comfort zone if your water drifts. | 10 gal+ |
| Avoid | Angelfish | Pygmy corydoras are small enough for adult angelfish to eat. | — |
| Avoid | Common goldfish | Common goldfish need cool water; pygmy corydoras need tropical water. | — |
| Avoid | Fancy goldfish | Fancy goldfish need cool water; pygmy corydoras need tropical water. | — |
Setup and care
| Heater | Yes. Set an adjustable heater to 72–78°F (22–26°C); pygmy corydoras tolerate 72–79°F, and most rooms are cooler than that. |
|---|---|
| Feeding | Sinking foods, flakes, frozen food, wafers; live foods in addition |
| Substrate | Fine sand to protect barbels |
| New tanks | Add only to an established, cycled tank. Not for a brand-new setup. |
| Males vs females | Females are larger, rounder and broader, especially with eggs |
| Male:female ratio | 2 males per female (for breeding) |
| Breeding | Adults eat the eggs; fry need extra care due to size |
Watch out for
- Easily intimidated by larger tankmates and won't compete well for food
- Barbel infections if kept in dirty conditions
- Sharp pectoral spines can sting and catch in nets
- Needs sinking foods
- Shy in small groups
- Slow eaters, can be outcompeted for food
Care tips
- Keep a group of at least 8, since pygmy corydoras are shy in small groups.
- Use fine sand as a substrate to protect their barbels, and keep the tank clean to avoid barbel infections.
- Do frequent partial water changes, because they are sensitive to elevated nitrates, and add them only to a mature tank.
- Use a tight-fitting lid in case they jump, but leave a gap under the cover so they can breathe air.
Questions
Do pygmy corydoras need a heater?
They tolerate temperatures from 72 to 79°F, and the ideal range is 72 to 78°F. If your room stays within that range, you may not need one; if it doesn't, a heater will help you keep the tank there.
What do pygmy corydoras eat?
They are omnivores and need sinking foods, such as sinking wafers, flakes and frozen food. Live foods are a good addition. Frozen bloodworms are too big for them, and because they are slow eaters, make sure they aren't being outcompeted for food.
What fish can live with pygmy corydoras?
Good matches include ember tetras, neon tetras, betta fish, cherry shrimp and other pygmy corydoras. Use caution with guppies, zebra nerite snails and tiger barbs, which can harass them. Avoid angelfish, common goldfish and fancy goldfish, which can eat them. They aren't suited to a general community tank, since larger tankmates can intimidate them.
How many pygmy corydoras should I keep together?
Keep at least 8. They are shy in small groups, and a larger group helps them feel secure.
How big do pygmy corydoras get, and how can I tell males from females?
Adults reach about 1 inch. Females are larger, rounder and broader than males, especially when carrying eggs. For breeding, aim for 2 males per female. Be aware that adults eat the eggs, and the fry need extra care because of their size.
Sources
Each value is cross-checked across the references below. Where they disagreed, an editor chose a value and recorded why.
- Pygmy corydoras (en.wikipedia.org)
- Corydoras pygmaeus (Seriously Fish) (www.seriouslyfish.com)
- Care Guide for Pygmy Corydoras – The World's Tiniest ... (www.aquariumcoop.com)
- Pygmy Cory-Gastrodermus pygmaeus (www.fishkeeper.co.uk)
- How Big Do Pygmy Corydoras Get | Size and Care Guide (shrimpybusiness.com)
- GBIF taxonomy record
- Wikidata entry
Where each value comes from (22 facts)
| Fact | What each source says |
|---|---|
| Temperature | en.wikipedia.org: “a temperature range of 22–26 °C (72–79 °F)” seriouslyfish.com: “Temperature: 22 – 26 °C72 – 79 °F” aquariumcoop.com: “temperatures between 72–78°F (22–26°C)” fishkeeper.co.uk: “Temperature 22-26°C” shrimpybusiness.com: “Temperature: 72°F to 78°F” |
| pH editor decision | en.wikipedia.org: “water with a 6.0 - 8.0 pH, a water hardness of 2 – 25 dGH” seriouslyfish.com: “pH: 6.4 to 7.4” aquariumcoop.com: “they are used to pH of 6.4–7.5 and moderately soft water” fishkeeper.co.uk: “pH: 6.0-7.2, dH: up to 15 degrees.” shrimpybusiness.com: “pH Level: 6.2 to 7.4” |
| Adult size | en.wikipedia.org: “typical adult sizes are 1.9 centimeters (0.75 in) for males and 2.5 centimeters (1.0 in) for females” seriouslyfish.com: “Max size 30mm SL1.2in SL” aquariumcoop.com: “grows to a grand total of 1 inch (2.5 cm) in length” fishkeeper.co.uk: “Maximum Size 3cm (1.2")” shrimpybusiness.com: “At maturity, this species gets up to 1 inch long with males being slightly smaller than females.” |
| Group size editor decision | en.wikipedia.org: “They are schooling fish that are usually kept in groups of at least four” seriouslyfish.com: “so it's best to buy at least 6, preferably 10 or more.” aquariumcoop.com: “keep a bigger school of at least 8–12 pygmies that will be less afraid to come out.” fishkeeper.co.uk: “Pygmy Corys should always be maintained in large sized groups of at least 10 specimens” shrimpybusiness.com: “they prefer to be kept in schools with at least six of their own kind.” |
| Temperament | en.wikipedia.org: “It is a peaceful fish, shoaling fish and can be kept in a community aquarium of smaller fish species such as ember tetras.” seriouslyfish.com: “It's very peaceful, but doesn't make an ideal community fish due to its small adult size.” aquariumcoop.com: “pygmy corys are very peaceful community fish that wouldn’t harm a fly.” fishkeeper.co.uk: “The Pygmy Cory is a peaceful little species, ideally suited to smaller softwater aquaria.” shrimpybusiness.com: “If you’re looking for a peaceful addition to a nano tank or small freshwater aquarium” |
| Swims | en.wikipedia.org: “they often swim in shoals around the mid water and lower regions of the tank.” seriouslyfish.com: “as it tends to inhabit the middle levels of the tank.” aquariumcoop.com: “pygmy corys have the unusual habit of hovering midwater by flapping their fins” fishkeeper.co.uk: “this delightful species spends a good deal of time hovering in midwater.” shrimpybusiness.com: “this species tends to occupy the middle as well as the lower level of an aquarium.” |
| Diet | en.wikipedia.org: “It feeds on worms, benthic crustaceans, insects, and plant matter.” |
| Eats shrimp/snails | en.wikipedia.org: “It can be kept with small shrimp and snails.” shrimpybusiness.com: “They also tend to do well with freshwater snails and dwarf shrimp.” |
| Water type | en.wikipedia.org: “is a species of freshwater ray-finned fish belonging to the subfamily Corydoradinae” shrimpybusiness.com: “Corydoras are freshwater catfish that are widely distributed throughout South America.” |
| Breeding type | en.wikipedia.org: “she attaches the sticky eggs to a surface, where they will remain for about three days before hatching.” seriouslyfish.com: “she deposits a single egg. Once this is fertilised, she swims away to find a suitable place to deposit the egg” aquariumcoop.com: “the female pygmy will deposit a single, sticky egg — about 1 mm in diameter — on a strand of java moss” fishkeeper.co.uk: “The 1mm eggs (numbering up to 100 per female) are individually deposited, usually on the glass or amongst fine-leaved plants.” shrimpybusiness.com: “pygmy cories don’t lay clusters of eggs—they deposit them singly in different locations around the tank.” |
| Native to | en.wikipedia.org: “This catfish is found in the Madeira River basin in Brazil.” seriouslyfish.com: “appears to be endemic to the Rio Madeira basin, Brazil.” aquariumcoop.com: “Pygmy corydoras were originally discovered in the river basins of Brazil” fishkeeper.co.uk: “Distribution Rio Madeira, Brazil” shrimpybusiness.com: “tributaries of the Aguarico River in Ecuador and the Madeira River in western Brazil” |
| Hardness (GH) editor decision | en.wikipedia.org: “a water hardness of 2 – 25 dGH” seriouslyfish.com: “Hardness 0–8dGH” |
| Telling males from females | en.wikipedia.org: “females are also rounder and broader than males, especially when they have eggs.” seriouslyfish.com: “Females are noticeably rounder and broader bodied than males, especially when full of eggs. They're often also slightly larger.” aquariumcoop.com: “with females being slightly rounder and longer than males.” fishkeeper.co.uk: “Females grow slightly larger and appear wider when viewed from above.” shrimpybusiness.com: “males being slightly smaller than females.” |
| Substrate | en.wikipedia.org: “kept on fine grained substrate, such as sand. This enables them to dig through the substrate without injury to their barbels” seriouslyfish.com: “Use a substrate of river sand and add a few driftwood branches” fishkeeper.co.uk: “There should be a sandy substrate in order to protect the delicate sensory barbels” |
| Feeding | en.wikipedia.org: “It can be fed most sinking foods, flakes, frozen food and sinking wafers.” seriouslyfish.com: “Any food offered must be small enough for its tiny mouth.” aquariumcoop.com: “frozen daphnia, cyclops, and baby brine shrimp are perfectly bite-sized.” fishkeeper.co.uk: “Offer a variety of appropriately sized foods, such as small sinking catfish pellets, micro granules, crushed flake, mini-bloodworm” shrimpybusiness.com: “The best diet for pygmy cories is a nutritionally complete sinking wafer or pellet-style food formulated specifically for bottom feeders or catfish.” |
| Smallest tank | seriouslyfish.com: “~41 litres~11 US gal” aquariumcoop.com: “get a 10-gallon or larger aquarium so that you can keep a bigger school of at least 8–12 pygmies” shrimpybusiness.com: “Tank Size: 10 gallons minimum” |
| Care level editor decision | seriouslyfish.com: “Difficulty5 of 8 measures Moderate” |
| Male:female ratio | seriouslyfish.com: “2 males per female is recommended.” fishkeeper.co.uk: “a ratio of 2 males to every female tends to work best.” |
| Breeding | seriouslyfish.com: “The adults will eat the eggs given the opportunity” aquariumcoop.com: “pygmy corys may not be as easy to breed as bronze or albino corys (C. aeneus), many hobbyists have had success with them in home aquariums.” fishkeeper.co.uk: “This species is said to be a little more difficult to breed than other members of the genus, as it can be difficult to raise the miniscule fry.” shrimpybusiness.com: “pygmy cories are a little bit trickier. To breed pygmy cories, you’ll need a fully mature tank filled with live plants” |
| Lifespan | shrimpybusiness.com: “Lifespan: 3-5 years” |
| Carbonate hardness (KH) | shrimpybusiness.com: “KH: 6-10 dKH” |
| Mature tank only | shrimpybusiness.com: “Before purchasing pygmy corydoras, make sure your tank is fully cycled and stable.” |
Editor decisions (4)
- Seriously Fish 6.4–7.4, Aquarium Co-op 6.4–7.5, Maidenhead 6.0–7.2: slightly acidic to neutral.
- Sources range 4–10; Seriously Fish prefers 10+, Aquarium Co-op 8–12. Larger groups are bolder, so we use 8.
- Seriously Fish 0–8 dGH, Wikipedia 2–25; soft to moderately hard water.
- Easy once settled in a mature tank; Seriously Fish rates them moderate because they're delicate when new.