Pygmy Corydoras
A tiny, peaceful shoaling catfish with a big personality. Learn how to create the right environment, feed them well and watch a proper shoal come to life.
Meet the Pygmy Corydoras
Tiny body, huge personality. Pygmy Corydoras are one of the smallest corydoras available to aquarists and are loved for their peaceful nature, active shoaling behaviour and adorable appearance.
Despite their common name, Pygmy Corydoras don't behave exactly like larger corydoras. They can spend considerable time swimming and shoaling in the mid-water rather than staying exclusively on the bottom.
They are a particularly interesting choice for planted community aquariums, where a group can move through the aquarium together before settling down to forage.
Keep them in a proper group, give them clean stable water, provide plenty of cover and make sure food is small enough for their tiny mouths.
Pygmy Corydoras at a glance
FishBase records Gastrodermus pygmaeus from the Madeira River basin and gives a temperature range of 22–26°C and pH range of 6.0–8.0. Recorded maximum standard length is 2.1 cm, although aquarium specimens are often described as reaching around 2.5–3 cm depending on the source and measurement method.
Natural habitat & behaviour
Pygmy Corydoras originate from freshwater systems in South America, including the Madeira basin. They are associated with tropical freshwater environments and are naturally social fish.
Their small size makes numbers important. A lone pygmy may survive, but it won't display the same natural social behaviour as a proper shoal.
Keep a shoal
A group gives them confidence and encourages their natural social and swimming behaviour.
Give them cover
Plants, wood and other gentle cover create places to rest and retreat when they want to feel secure.
Keep water moving
Provide clean, well-oxygenated water without creating a current that constantly pushes these tiny fish around.
Expect mid-water activity
Unlike many larger corydoras, pygmies frequently leave the bottom and shoal through the open water.
Aquarium setup
A mature, stable aquarium is much more important than simply choosing a particular tank volume. Because Pygmy Corydoras are social and active, provide enough swimming length for the group rather than focusing only on height.
Substrate
Choose a fine, smooth substrate, such as aquarium sand or another rounded, non-abrasive option. This allows natural foraging behaviour and avoids unnecessarily rough surfaces around their sensitive barbels.
Plants & cover
Live plants are excellent additions. Dense planting, floating plants, driftwood and other decor can create shaded areas and give the fish somewhere to retreat.
Filtration
Use mature biological filtration with gentle-to-moderate flow. Good oxygenation and clean water are important, but the fish should still be able to swim comfortably rather than constantly fighting the current.
Leave some open swimming space while creating planted areas around the edges and places where the shoal can rest.
Water parameters
Stability matters. Pygmy Corydoras should be kept in clean, mature aquarium water rather than chasing numbers with constant adjustments.
| Parameter | Recommended target | Notes |
|---|---|---|
| Temperature | 22–26°C | Matches the range reported for the species. |
| pH | About 6.0–7.5 | Stable, suitable water is preferable to constant adjustment. |
| Ammonia | 0 ppm | Should be undetectable in an established aquarium. |
| Nitrite | 0 ppm | Should be undetectable in an established aquarium. |
| Nitrate | Keep controlled | Manage through appropriate water changes, plants and stocking. |
A stable aquarium within a suitable range is generally preferable to repeatedly changing water chemistry in an attempt to hit one exact number.
Feeding Pygmy Corydoras
Pygmy Corydoras are omnivorous and should receive a varied diet of appropriately sized foods.
Their tiny mouths mean that food size is especially important. Large pellets or wafers may be difficult for them to eat effectively.
Micro pellets
Choose small sinking foods that can be eaten comfortably by tiny fish.
Frozen foods
Suitable small frozen foods can add variety and encourage natural feeding behaviour.
Baby brine shrimp
A useful high-quality food for small fish and particularly useful when conditioning adults.
Variety
Rotate suitable foods rather than relying on a single food every day.
In a busy community aquarium, larger or faster fish can consume food before pygmies get enough. Feed small portions in several areas when necessary and watch the shoal actually eat.
How many should you keep?
Pygmy Corydoras are schooling fish and are best kept in a proper group. While smaller groups may survive, larger groups generally provide more confidence and allow their natural social behaviour to become much more obvious.
Aquarium Co-Op recommends groups of around 8–12 in a 10-gallon or larger aquarium, while other care references recommend similar group sizes. :contentReference[oaicite:2]{index=2}
Tank mates
Pygmy Corydoras are peaceful community fish and can work well with other small, peaceful freshwater species.
Good companions
- Small peaceful rasboras
- Small tetras
- White Cloud Mountain Minnows where temperature requirements overlap
- Small peaceful livebearers where water parameters are compatible
- Freshwater shrimp
- Peaceful snails
Avoid
- Large predatory fish
- Aggressive or highly territorial species
- Fish large enough to view pygmies as food
- Extremely boisterous tank mates that constantly outcompete them for food
The biggest risk isn't that pygmies will bother other fish — it's that larger or aggressive fish may intimidate, injure or eat them.
Understanding their behaviour
One of the most entertaining things about Pygmy Corydoras is watching a healthy group behave naturally.
Schooling
They often move together through the aquarium, particularly when they feel secure.
Mid-water swimming
They regularly leave the substrate and hover or cruise through open water.
Foraging
They constantly investigate surfaces and substrate looking for food.
Resting
They may settle on leaves, wood or the substrate between periods of activity.
Breeding Pygmy Corydoras
Pygmy Corydoras can breed in aquariums when conditions are suitable. FishBase records females holding small batches of eggs between their pelvic fins before fertilisation and attachment of the sticky eggs to a suitable surface. :contentReference[oaicite:3]{index=3}
A varied diet, excellent water quality and regular maintenance can help condition adults for spawning.
What happens during spawning?
The female carries a small number of eggs between her pelvic fins while the male fertilises them. She then attaches the eggs to a suitable surface, with the process repeated for multiple eggs.
If you want to raise fry, protecting the eggs from being eaten and providing suitably tiny foods for newly hatched fry become important considerations.
Health & common problems
Most problems with pygmies are best prevented through good aquarium husbandry rather than treated after the fact.
Signs something may be wrong
- Persistent lethargy
- Rapid or laboured breathing
- Loss of appetite
- Unusual isolation from the group
- Clamped fins
- Sudden changes in swimming behaviour
- Unexpected deaths
When several fish suddenly behave differently, checking ammonia, nitrite, nitrate, temperature and other relevant parameters is one of the most useful first steps.
Frequently asked questions
Are Pygmy Corydoras bottom-dwelling fish?
They forage on the bottom but are unusual among corydoras because they also spend significant time swimming and shoaling in the mid-water.
How many Pygmy Corydoras should I keep?
A group of 8 or more is a good practical target. Larger groups can provide greater confidence and more natural social behaviour when the aquarium has enough space.
Can Pygmy Corydoras live with shrimp?
Yes. They are peaceful and are generally compatible with adult freshwater shrimp. Very small shrimp fry may still be vulnerable to opportunistic feeding.
Do Pygmy Corydoras need sand?
A fine, smooth substrate is strongly recommended because it allows natural foraging and avoids unnecessarily abrasive surfaces around their barbels.
Can Pygmy Corydoras live in a 20 litre aquarium?
Although their tiny adult size can make them seem suitable for very small aquariums, a stable, appropriately filtered aquarium with enough swimming length and space for a proper shoal is preferable. Around 40 litres or more is a more comfortable practical starting point for a group.
Do Pygmy Corydoras eat algae?
They should not be considered an algae-eating fish. They are omnivores and should be fed an appropriate varied diet.
Are Pygmy Corydoras suitable for beginners?
Yes, provided the aquarium is mature, stable and properly maintained. Their small size makes them appealing, but their tiny mouths, social nature and sensitivity to poor water quality still need to be taken seriously.
Small fish. Big personality. 💙
Give Pygmy Corydoras clean, stable water, a proper shoal, suitable food and a peaceful environment — and you'll get to see one of the most charming little fish in the hobby doing what they do best: exploring together.
Research & further reading
Species information and care recommendations for this guide were checked against FishBase and established aquarium-care references.
- FishBase — Gastrodermus pygmaeus species summary. :contentReference[oaicite:4]{index=4}
- Aquarium Co-Op — Pygmy Corydoras care and aquarium setup. :contentReference[oaicite:5]{index=5}
- Fishipedia — Pygmy Corydoras habitat and environmental information. :contentReference[oaicite:6]{index=6}