Photo: Birger A (CC BY-SA 3.0) — via Wikimedia Commons
Pygmy Corydoras (Corydoras pygmaeus)
The cory that dares swim in open water — a shimmering, pencil-thin shoal of these 2.5 cm dwarfs fills the midwater of a nano tank like no other bottom-dweller.
Will it live with a Pygmy Corydoras?
We compare each fish against your pygmy corydoras on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- African Dwarf Frog✅ CompatiblePeaceful · 4 cm · Medium care · 22–26 °C (72–79 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Amapá Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 24–27 °C (75–81 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Amapá Tetra in a shoal of 6+ or it gets stressed and nippy.
- Assassin Snail✅ CompatiblePeaceful · 3 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Blackwing Hatchetfish✅ CompatiblePeaceful · 3.5 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Blackwing Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
- Blue Danio✅ CompatiblePeaceful · 4 cm · Easy care · 21–26 °C (70–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Blue Danio in a shoal of 6+ or it gets stressed and nippy.
- Blue Emperor Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 23–27 °C (73–81 °F)
- Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Blue Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
- Cardinal Tetra✅ CompatiblePeaceful · 4 cm · Medium care · 23–27 °C (73–81 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
- Cherry Shrimp✅ CompatiblePeaceful · 3 cm · Easy care · 18–28 °C (64–82 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Cherry Shrimp in a shoal of 10+ or it gets stressed and nippy.
- Clown Killifish✅ CompatiblePeaceful · 3.5 cm · Medium care · 22–26 °C (72–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
- Crimson Red Betta✅ CompatiblePeaceful · 3.5 cm · Hard care · 24–29 °C (75–84 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Endler's Livebearer✅ CompatiblePeaceful · 3 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Endler's Livebearer in a shoal of 6+ or it gets stressed and nippy.
- Eyespot Rasbora✅ CompatiblePeaceful · 3.5 cm · Medium care · 20–25 °C (68–77 °F)
- Compatible on the things that matter: shared water near 22–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Eyespot Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Fire Red Licorice Gourami✅ CompatiblePeaceful · 3.5 cm · Hard care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Glowlight Danio✅ CompatiblePeaceful · 3 cm · Easy care · 22–26 °C (72–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Glowlight Rasbora✅ CompatiblePeaceful · 3.5 cm · Easy care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
- Gold Ring Danio✅ CompatiblePeaceful · 3 cm · Easy care · 18–26 °C (64–79 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Gold Ring Danio in a shoal of 8+ or it gets stressed and nippy.
- Lambchop Rasbora✅ CompatiblePeaceful · 3 cm · Medium care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Lambchop Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Malaysian Trumpet Snail✅ CompatiblePeaceful · 3 cm · Easy care · 21–27 °C (70–81 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Neon Tetra✅ CompatiblePeaceful · 3 cm · Easy care · 20–26 °C (68–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Neon Tetra in a shoal of 6+ or it gets stressed and nippy.
- Northern Glowlight Danio✅ CompatiblePeaceful · 3.5 cm · Medium care · 18–24 °C (64–75 °F)
- Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
- Tail-spot Corydoras✅ CompatiblePeaceful · 3 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Tail-spot Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Tailspotted Oto✅ CompatiblePeaceful · 3.5 cm · Medium care · 22–27 °C (72–81 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Tailspotted Oto in a shoal of 6+ or it gets stressed and nippy.
- Tiger Shrimp✅ CompatiblePeaceful · 3 cm · Hard care · 20–25 °C (68–77 °F)
- Compatible on the things that matter: shared water near 22–25 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Tiger Shrimp in a shoal of 6+ or it gets stressed and nippy.
- Trinidad Guppy✅ CompatiblePeaceful · 3 cm · Easy care · 19–24 °C (66–75 °F)
- Both are peaceful, and their water overlaps around 22–24 °C — no size, zone or temperament conflicts.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Black Darter Tetra⚠️ With cautionSemi-aggressive · 4 cm · Hard care · 21–28 °C (70–82 °F)
- Black Darter Tetra and Pygmy Corydoras are close in size, but the semi-aggressive one tends to dominate — add pygmy corydoras in a group to spread the pressure.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Black Ruby Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Black Ruby Barb is semi-aggressive and may chase or nip the smaller Pygmy Corydoras — plant heavily and break up sight lines.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Black Ruby Barb in a shoal of 6+ or it gets stressed and nippy.
- Black Skirt Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Black Skirt Tetra clearly outsizes Pygmy Corydoras and is semi-aggressive; risky unless the tank is big and well-planted.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Desert Goby⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
- Desert Goby clearly outsizes Pygmy Corydoras and is semi-aggressive; risky unless the tank is big and well-planted.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Dwarf Chain Loach⚠️ With cautionPeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
- Eastern Betta⚠️ With cautionSemi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
- Expect Eastern Betta to harass Pygmy Corydoras at times; give dense cover and watch them at feeding.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- GloFish Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °F)
- GloFish Tetra clearly outsizes Pygmy Corydoras and is semi-aggressive; risky unless the tank is big and well-planted.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep GloFish Tetra in a shoal of 6+ or it gets stressed and nippy.
- Humpbacked Tetra⚠️ With cautionSemi-aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Expect Humpbacked Tetra to harass Pygmy Corydoras at times; give dense cover and watch them at feeding.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Humpbacked Tetra in a shoal of 8+ or it gets stressed and nippy.
- Morse Code Corydoras⚠️ With cautionPeaceful · 5 cm · Medium care · 23–26 °C (73–79 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Morse Code Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Rainbow Emperor Tetra⚠️ With cautionSemi-aggressive · 3.6 cm · Medium care · 22–28 °C (72–82 °F)
- Rainbow Emperor Tetra is semi-aggressive and may chase or nip the smaller Pygmy Corydoras — plant heavily and break up sight lines.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
- Serpae Tetra⚠️ With cautionSemi-aggressive · 4 cm · Easy care · 23–28 °C (73–82 °F)
- Expect Serpae Tetra to harass Pygmy Corydoras at times; give dense cover and watch them at feeding.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Serpae Tetra in a shoal of 6+ or it gets stressed and nippy.
- Silvertip Tetra⚠️ With cautionSemi-aggressive · 5 cm · Easy care · 22–28 °C (72–82 °F)
- Expect Silvertip Tetra to harass Pygmy Corydoras at times; give dense cover and watch them at feeding.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Silvertip Tetra in a shoal of 6+ or it gets stressed and nippy.
- Spotfin Betta⚠️ With cautionSemi-aggressive · 5 cm · Medium care · 23–28 °C (73–82 °F)
- Expect Spotfin Betta to harass Pygmy Corydoras at times; give dense cover and watch them at feeding.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Striped Red-Eye Puffer⚠️ With cautionAggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
- Striped Red-Eye Puffer is aggressive and may chase or nip the smaller Pygmy Corydoras — plant heavily and break up sight lines.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Tiger Badis⚠️ With cautionSemi-aggressive · 4 cm · Medium care · 22–24 °C (72–75 °F)
- Tiger Badis and Pygmy Corydoras are close in size, but the semi-aggressive one tends to dominate — add pygmy corydoras in a group to spread the pressure.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Wine Red Betta⚠️ With cautionAggressive · 5 cm · Medium care · 24–28 °C (75–82 °F)
- Expect Wine Red Betta to harass Pygmy Corydoras at times; give dense cover and watch them at feeding.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Discus⛔ Not recommendedPeaceful · 20 cm · Hard care · 28–31 °C (82–88 °F)
- Temperature needs don't overlap (Pygmy Corydoras 22–26 °C vs Discus 28–31 °C).
- Your 75 L tank is below the ~200 L this pairing really wants — crowding raises aggression.
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
- Keep Discus in a shoal of 6+ or it gets stressed and nippy.
- German Blue Ram⛔ Not recommendedPeaceful · 6 cm · Hard care · 27–30 °C (81–86 °F)
- Temperature needs don't overlap (Pygmy Corydoras 22–26 °C vs German Blue Ram 27–30 °C).
- Keep Pygmy Corydoras in a shoal of 8+ or it gets stressed and nippy.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Pygmy Corydoras care specs
- Care level
- Easy
- Breeding
- Medium
- Max size
- 3.2 cm (1.3 in)
- Min tank size
- 60 L (15.9 gal)
- Temperature
- 22–26 °C (72–79 °F)
- pH
- 6–7.5
- Hardness
- 2–12 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- All
- Group size
- 8+ (shoaling)
- Family
- Callichthyidae
- Origin
- South America — Rio Madeira basin, Brazil
What is a Pygmy Corydoras?
The pygmy corydoras (Corydoras pygmaeus) is one of the tiniest members of the armoured catfish family Callichthyidae, reaching a maximum of just 3.2 cm (about 1.25 in). That compact size, combined with an unusually active, open-water shoaling habit, makes it one of the most characterful nano fish available in the hobby. Where most cories hug the substrate and disappear into decoration, a group of pygmy cories cruises every level of the tank in a tight, shimmering ribbon — silver bodies split by a crisp black lateral stripe running from snout to tail.
Despite its miniature proportions, the pygmy corydoras is a hardy fish with straightforward care needs, making it a genuinely good choice for adult fishkeepers setting up a planted nano community or a species-only biotope. The challenge is less about water chemistry and more about respecting its social nature: a lone pygmy cory or a pair will be stressed and rarely seen; a shoal of eight or more becomes one of the most animated displays a small tank can offer.
Where do Pygmy Corydoras come from?
Pygmy corydoras are native to South America, specifically the Rio Madeira basin in Brazil, one of the largest tributary systems of the Amazon. In the wild they inhabit shallow, slow-moving stretches of stream and flooded forest margins where the water is warm, soft, darkly tinted with tannins from decaying leaf litter, and loaded with fine sediment. Overhanging vegetation and dense aquatic plants provide shade and refuge.
Understanding this origin shapes every aspect of good husbandry. These fish evolved in soft, slightly acidic water with minimal current and a fine, silty riverbed — conditions worth replicating closely. A biotope aquarium with dark substrate, driftwood, dried Indian almond leaves, and a gentle flow from a sponge filter is an ideal recreation of their home environment.
What size tank does a Pygmy Corydoras need?
The minimum recommended tank size is 60 litres (about 16 gallons), and that is built around the social requirement rather than the fish’s physical size. A shoal of eight fish — the minimum group size to keep them behaviorally healthy — needs enough horizontal floor space to forage comfortably and enough open midwater to cruise.
A 60 L tank with a footprint of around 60 × 30 cm or larger works well for a group of eight to twelve. If you plan to keep fifteen to twenty — which will produce a genuinely spectacular display — a 75–80 L (20 gal) tank is more appropriate. Prioritise floor area over height: a long, shallow aquarium serves pygmy cories better than a tall column tank. A lid is sensible, as with most small fish, though pygmy cories are not persistent jumpers.
What water parameters do Pygmy Corydoras need?
- Temperature: 22–26 °C (72–79 °F). Stable and on the cooler side of tropical — avoid the upper-end heat often recommended for discus or other Amazon species.
- pH: 6.0–7.5. Slightly acidic to neutral suits them well; wild-caught individuals appreciate the lower end of this range.
- Hardness: 2–12 dGH. Soft to moderately hard water is accepted, but very soft water (2–6 dGH) and a pH around 6.5–7.0 represents the sweet spot.
Consistency matters far more than hitting a precise number. Cycle the tank fully before adding fish, perform weekly water changes of around 20–30 %, and avoid sudden temperature or chemistry swings. Because pygmy cories are small-bodied, they are more sensitive to ammonia and nitrite spikes than larger fish — good biological filtration and a stable routine are the real keys to long-term health.
What do Pygmy Corydoras eat?
Pygmy corydoras are omnivores with a strong preference for small, protein-rich foods. In the wild they sift through fine substrate for micro-organisms, worms, tiny crustaceans, and organic detritus. In the aquarium, the feeding strategy should match that natural variety:
- Sinking micro-pellets or nano wafers as a daily staple — choose a size they can actually mouth; standard-sized cory wafers are often too large.
- Frozen or live baby brine shrimp (nauplii) — an excellent protein source that also triggers strong feeding responses.
- Micro worms and white worms — eagerly taken and useful for conditioning.
- Daphnia — good nutritional variety and a mild natural laxative.
- Fine-crushed flake — acceptable as a supplement but should not be the main diet.
Feed once or twice daily in small amounts. Because pygmy cories also patrol midwater, they will intercept food as it sinks — but ensure some reaches the bottom where they forage. Avoid leaving uneaten food to decompose, which will spike ammonia in a small tank quickly.
Are Pygmy Corydoras aggressive — and what fish can live with them?
Pygmy corydoras are entirely peaceful and present no aggression toward any tank mate. The only genuine compatibility concern runs in the other direction: they are small enough to be eaten by any fish with a mouth large enough to swallow a 3 cm fish whole, so tank-mate selection is about protecting the cories, not worrying about what they might harm.
Ideal companions in a nano community are other small, peaceful soft-water species — ember tetras, chili rasboras, celestial pearl danios, rummy-nose tetras (in larger tanks), small rasboras, and dwarf shrimp all coexist without issue. Avoid larger cichlids, most gouramis of medium size, aggressive barbs, and any fish that treats small bottom-dwellers as food. Bettas are sometimes kept alongside pygmy cories successfully, but outcomes depend entirely on the individual betta’s temperament.
For a detailed, filterable list of proven companions, see Pygmy Corydoras tank mates.
How do you tell male and female Pygmy Corydoras apart?
Sexual dimorphism in pygmy corydoras is subtle but consistent. Females are noticeably rounder and slightly larger, particularly visible when viewed from above — a gravid female has a distinctly plump, wide-bodied outline compared to the slimmer male. Males are more slender throughout, with a narrower, more streamlined body profile. The difference is easiest to spot in a mature group where both sexes are present side by side. In juveniles or single-sex groups the distinction is much harder to call with confidence.
How do Pygmy Corydoras breed?
Breeding pygmy corydoras is achievable in a home aquarium and rated medium difficulty — not because the fish are particularly secretive about the process, but because raising the small fry requires attention and appropriate foods.
Conditioning begins with a varied, protein-rich diet and ideally a slight temperature drop of 2–3 °C to simulate the onset of the rainy season, which triggers spawning in the wild. In a well-maintained tank with a healthy, mixed-sex shoal, spawning often occurs spontaneously. The female clasps the male in a T-position embrace, fertilises a small batch of eggs, and then places them — held against her belly by her pelvic fins — onto plant leaves, the glass, or fine-leafed vegetation. Clutches are small, typically 10–50 eggs laid over several sessions.
Eggs are best removed to a separate container with gentle aeration to prevent fungal loss and protect them from other tank inhabitants. They hatch in three to five days at typical temperatures. The fry are tiny and require infusoria, powdered fry food, or freshly hatched baby brine shrimp nauplii as first foods. Water quality management in the fry tank is critical — small water changes daily help keep conditions stable without shocking the delicate young fish.
What are common Pygmy Corydoras diseases?
Pygmy corydoras are generally robust when kept in appropriate conditions, but their small size and sensitivity to water quality mean problems escalate quickly if neglected.
- Barbel erosion / infection: The most common issue. Coarse substrate or poor water quality causes the sensitive facial barbels to erode and become infected. Prevented entirely by using fine sand substrate and keeping nitrates low.
- Ich (white spot): Small white grains on the body and fins, caused by Ichthyophthirius multifiliis. Stress and temperature drops are the usual triggers. Stable, warm water and good husbandry prevent most outbreaks. Quarantine new fish before adding them to the display tank.
- Fungal and bacterial infections: Typically secondary to physical damage or chronic poor water quality. Clean, well-oxygenated water and appropriate substrate largely prevent these.
- Red blotch disease: Reddening at the base of fins or on the belly, associated with bacterial infection and often linked to deteriorating water conditions. Address water quality first.
Health note: Identifying and treating fish diseases accurately requires more than a care profile. Confirm symptoms against a reputable veterinary or aquatic health resource before medicating — many conditions look similar, and the wrong treatment can cause additional stress to small, sensitive fish.
How long do Pygmy Corydoras live?
With good care, pygmy corydoras live 3–5 years. That lifespan is solid for a fish of their size and places them in the same range as many popular nano species. The factors that most reliably extend their lives are also the most straightforward: a fine sand substrate that protects their barbels, consistently clean water, a large enough shoal to keep them behaviourally healthy, and a varied diet. Fish kept in these conditions will remain active and visible throughout their lives; those kept in poor conditions or in groups that are too small often become stressed and short-lived without obvious cause.
Frequently asked questions
Why do pygmy corydoras swim in the middle of the tank instead of the bottom?
Unlike most cories, pygmy corydoras are active midwater shoalers as well as bottom foragers. In a tight group of eight or more they will cruise all levels, darting to the surface for air and retreating to the substrate to pick at food. This unusual behaviour makes them one of the few nano fish that genuinely fill the middle layer.
How many pygmy corydoras should I keep together?
A minimum of eight, and more is always better. They draw confidence from the group — a shoal of ten or twelve will be bolder, more active, and less likely to hide. In a species tank or nano community you can keep twelve to twenty in a 60–80 L tank without issue.
What you need to keep a pygmy corydoras
The baseline is a heated, filtered 60 L+ tank: a reliable heater to hold 22–26 °C (72–79 °F), a gentle filter that won't batter a pygmy corydoras in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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