Common name
Pygmy cory
Scientific name
Gastrodermus pygmaeus
Category
Freshwater fish
Group
Corydoras-type catfish
Environment
Freshwater
Origin
Madeira River basin in South America
Care level
Beginner
Adult size
Up to about 2.1 cm standard length, with total length slightly greater
Expected lifespan
3–5 years
Minimum housing
60 L or larger with a wide footprint for a shoal of ten or more
Temperature
22–27 °C
pH
6.0–7.6
Hardness / minerals
Soft to moderately hard
Salinity
Freshwater
Lighting
Normal aquarium lighting
Placement / swimming zone
Lower and midwater

Identity and search names

Single-species profile for Gastrodermus pygmaeus, formerly Corydoras pygmaeus. Do not merge it with G. hastatus or Hoplisoma habrosum.

Search names: Pygmy corydoras, Corydoras pygmaeus

Environment and housing

Smooth sand or fine rounded substrate, oxygenated water and shaded resting areas.

Water stability: Maintain 22–27 °C; pH 6.0–7.6; minerals: Soft to moderately hard; salinity: Freshwater. Stability, dissolved oxygen and nitrogen-cycle control matter more than chasing one exact reading.

Feeding and nutrition

Feeding ecology: Omnivore; must receive sinking food

Feeding routine: Offer fine sinking micro-pellets and small frozen or cultured invertebrates in several locations. Confirm every fish has a rounded but not bloated abdomen.

Social structure and compatibility

10+; often swims in mid water as well as on the bottom

Good with peaceful community fish that do not monopolise the substrate. Retain a cycled separation option for aggression, feeding exclusion, predation, injury or disease.

Adult load and life support

Projected adult load: Low by biomass but high in feeding and observation risk because tiny fish can decline quickly while hidden in a community.

Filtration: Use mature gentle filtration with protected intakes and no stagnant waste pockets on the substrate.

Aeration: Maintain good oxygenation and unobstructed surface access without overpowering the shoal.

Maintenance: Siphon fine waste, inspect all fish for body condition, count the shoal and prevent larger tankmates monopolising food.

Breeding and reproduction

Adhesive egg layer. Do not compromise adult welfare, genetic identity, quarantine capacity, containment or lawful rehoming to attempt breeding.

Quarantine, welfare and risk

Quarantine: Quarantine new fish in a separate fully cycled system for at least 30 days at the intended temperature and mineral chemistry. Use dedicated equipment; observe appetite, respiration, faeces, skin, fins, gills and behaviour; never add transport water to the display.

Welfare checks: Track shoal cohesion, midwater activity, abdominal condition, barbel health and direct feeding access. Track individual body condition, feeding access, respiration, injury, abnormal hiding or aggression and use of the intended swimming zone.

Important warning

Small size does not make this a fish for tiny tanks. Keep a proper shoal and use tankmates too small and gentle to intimidate or eat it.

Main risk: Starvation, intake injury, predation and loss of normal social behaviour in undersized groups.

Australian biosecurity and release

Never release fish, fry, eggs, aquarium water, sediment, plants, live food or wet equipment into drains, dams or natural waterways. Australian import eligibility is species-specific: check the current permitted ornamental-fish list and BICON conditions by accepted scientific name. Import requires a permit, an approved source country and approved-arrangement isolation. Check current South Australian noxious-fish and movement rules before purchase, sale, transport, stocking or disposal.

Current check: Current lawful import, possession, stocking or movement must be checked by accepted scientific name. Absence from one state list is not import approval.

Detailed husbandry

Identity Scope
Single-species profile for Gastrodermus pygmaeus, formerly Corydoras pygmaeus. Do not merge it with G. hastatus or Hoplisoma habrosum.
Adult Size And Space
Expected adult size: Up to about 2.1 cm standard length, with total length slightly greater. Minimum permanent housing: 60 L or larger with a wide footprint for a shoal of ten or more. Adult dimensions, group or territory needs, swimming footprint, oxygen demand and waste production matter more than juvenile sale size.
Social Structure
10+; often swims in mid water as well as on the bottom
Swimming Zone
Primary zone: Lower and midwater. Keep that zone open enough for normal movement, feeding, refuge and escape.
Feeding Ecology
Omnivore; must receive sinking food
Feeding Plan
Offer fine sinking micro-pellets and small frozen or cultured invertebrates in several locations. Confirm every fish has a rounded but not bloated abdomen.
Water Stability
Maintain 22–27 °C; pH 6.0–7.6; minerals: Soft to moderately hard; salinity: Freshwater. Stability, dissolved oxygen and nitrogen-cycle control matter more than chasing one exact reading.
Adult Projected Load
Low by biomass but high in feeding and observation risk because tiny fish can decline quickly while hidden in a community.
Filtration
Use mature gentle filtration with protected intakes and no stagnant waste pockets on the substrate.
Aeration
Maintain good oxygenation and unobstructed surface access without overpowering the shoal.
Maintenance
Siphon fine waste, inspect all fish for body condition, count the shoal and prevent larger tankmates monopolising food.
Habitat Structure
Smooth sand or fine rounded substrate, oxygenated water and shaded resting areas.
Compatibility Plan
Good with peaceful community fish that do not monopolise the substrate. Retain a cycled separation option for aggression, feeding exclusion, predation, injury or disease.
Breeding Plan
Adhesive egg layer. Do not compromise adult welfare, genetic identity, quarantine capacity, containment or lawful rehoming to attempt breeding.
Quarantine
Quarantine new fish in a separate fully cycled system for at least 30 days at the intended temperature and mineral chemistry. Use dedicated equipment; observe appetite, respiration, faeces, skin, fins, gills and behaviour; never add transport water to the display.
Welfare Checks
Track shoal cohesion, midwater activity, abdominal condition, barbel health and direct feeding access. Track individual body condition, feeding access, respiration, injury, abnormal hiding or aggression and use of the intended swimming zone.
Biosecurity And Release
Never release fish, fry, eggs, aquarium water, sediment, plants, live food or wet equipment into drains, dams or natural waterways. Australian import eligibility is species-specific: check the current permitted ornamental-fish list and BICON conditions by accepted scientific name. Import requires a permit, an approved source country and approved-arrangement isolation. Check current South Australian noxious-fish and movement rules before purchase, sale, transport, stocking or disposal.
Main Risk
Starvation, intake injury, predation and loss of normal social behaviour in undersized groups.
Overridable Warnings
Small size does not make this a fish for tiny tanks. Keep a proper shoal and use tankmates too small and gentle to intimidate or eat it.

Sources

Current accepted identity or qualified trade identity, former names, adult scale, social structure, feeding ecology, adult projected load, filtration, aeration, maintenance, quarantine, welfare, Australian import controls and South Australian movement, stocking or no-release obligations were rechecked. AquaNexus wording is original.