Pygmy Corydoras Care
Short answer: Pygmy corydoras (Corydoras pygmaeus) are nano shoaling catfish for a 10-gallon-plus tank, kept in groups of at least six — ideally ten or more. Across real tanks, keepers run a median of 6 in a 10-gallon and 8 in a 20-gallon. Unlike bottom-dwelling common corys, pygmies shoal in mid-water.
Pygmy corydoras at a glance
- Scientific name
- Corydoras pygmaeus
- Adult size
- ~1″
- Temperature
- 72–79°F
- pH
- 6.2–7.4
- Minimum tank
- 10 gal
- Temperament
- peaceful
- Social
- schooling — keep 6+
- Reference
- Wikipedia
Pygmy corydoras (Corydoras pygmaeus, recently reclassified Gastrodermus pygmaeus1) are the nano member of the cory family — barely 3 cm, and the one cory that shoals out in mid-water rather than pottering along the bottom.
A nano shoaling catfish from Brazil’s Rio Madeira basin; keep a group of at least six — ideally ten or more.2
Pygmy corydoras at a glance
| Attribute | Authority | Real tanks (AquaGauge) |
|---|---|---|
| Adult size | ~3 cm (1.2 in)2 | — (smallest cory) |
| Temperature | 22–26 °C (72–79 °F)2 | genus median 78 °F |
| pH | 6.4–7.42 | genus median 7.5 |
| Minimum group | 6+ (10+ ideal)2 | median 6 in a 10-gal · 8 in a 20-gal |
| IUCN status | Least Concern1 | — |
Authority = recommended ranges for C. pygmaeus. "Real tanks" = our pygmy stocking data (22 tanks) + genus-level water from 676 corydoras tanks (no pygmy-specific water claimed). Figures are from the July 2026 snapshot (6,414 tanks total).
How many pygmy corydoras, and what tank size
Keep at least six — they are shoaling fish that only relax and swim in the open when there are enough of them. Across 22 real pygmy tanks in the AquaGauge dataset (July 2026 snapshot), keepers run a median of 6 in a 10-gallon (7 tanks, range 4-8) and 8 in a 20-gallon (11 tanks). A 10-gallon is the practical minimum; bigger is better because pygmies use horizontal swimming space, not just the floor. Plan a mixed tank in the stocking calculator or see the full how many corydoras breakdown.
Water and temperature
Pygmy corydoras want soft to neutral, stable water around 72-79 °F and pH 6.4-7.4.2 We do not hold pygmy-specific readings, but across our genus-wide corydoras water-parameter data keepers run a median of 78 °F and pH 7.5 — comfortably inside the pygmy’s range. As with any nano tank, stability matters more than chasing an exact number: a small water column swings fast.
Diet
Tiny mouths need tiny food. Pygmies are micro-scavengers, not an algae crew — feed crushed flake, micro/nano sinking pellets, microworms, and baby brine shrimp. Make sure food reaches them; in a community tank, faster mid-water fish will out-compete them at the surface.
Tankmates
Pygmy corydoras are peaceful and defenceless, so the rule is simple: nothing big enough to eat them. They pair beautifully with other nano fish — small rasboras, ember/neon tetras, shrimp, and a calm betta. Avoid angelfish, larger cichlids, and anything that treats a 3 cm fish as a snack.
Lifespan and breeding
Pygmy corydoras are shorter-lived than the larger corys because of their nano size — keepers generally report around three years, occasionally more, with stable water and a varied diet.
Breeding follows the genus pattern: a large, cooler water change triggers spawning, the female deposits sticky eggs on the glass and fine-leaved plants, and they hatch in about three to four days.2 Once their yolk sacs are absorbed, the tiny fry take microworm and baby brine shrimp over a thin layer of sand.2
Check your exact stocking
Add your fish below to see stocking %, filtration load and compatibility for your setup — live.
Planning a Pygmy corydoras tank. We start with your pygmy corydoras and filter the list to compatible tankmates — untick to see every species (incompatible ones get flagged).
Stocking — under 85% comfortable · 85–100% full · over 100% overstocked
Show the math
Gear for this setup
As an Amazon Associate AquaGauge earns from qualifying purchases. Some links below are affiliate links, at no extra cost to you. Current price and availability are shown on Amazon. Disclosure.
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AQUANEAT Bio Sponge Filter (up to 20 gal) Gentle, fry-safe filtration that won't suck in tiny pygmies; ideal for a nano shoal tank. Check price on Amazon → -
Aqua Natural Sugar White Sand (10 lb) Smooth, barbel-safe fine sand so pygmies can sift naturally without abrasion. Check price on Amazon → -
API Freshwater Master Test Kit Liquid tests for ammonia, nitrite, nitrate and pH — small water columns swing fast, so track them. Check price on Amazon →
FAQ
- How many pygmy corydoras in a 10-gallon tank?
- About six. Across real 10-gallon tanks the median is 6 (range 4-8). They are shoaling fish, so six is the floor; a 10-gallon comfortably holds 6-8.
- Do pygmy corydoras need to be in a group?
- Yes — at least 6, ideally 10 or more. In a tight shoal they swim out in the open mid-water; in small numbers they hide and do poorly.
- What size tank do pygmy corydoras need?
- A 10-gallon minimum. They are tiny (about 3 cm) but active mid-water shoalers that need swimming length, not just floor space.
- Do pygmy corydoras eat algae?
- No. Pygmy corydoras are micro-scavengers, not an algae crew. Feed small sinking foods, crushed flake, microworms and baby brine shrimp.
Sources
- Gastrodermus pygmaeus (Pygmy Corydoras), FishBase. View source ↗
- Corydoras pygmaeus, Seriously Fish. View source ↗
Freshwater aquarist of 8+ years.
