Not furry, but we like them anyway.

Pygmy Corydoras

Gastrodermus pygmaeus (Knaack, 1966); long known as Corydoras pygmaeus

Also called Pygmy cory, Pygmy catfish, Corydoras pygmaeus (former name)

SpeciesShort profile

From Rio Madeira basin in Brazil, in small tributaries, creeks and flooded forest; also reported from tributaries of the Nanay River in Peru and the Aguarico River in Ecuador.1 2 3

At a glance the quick version

Length2.1 to 3.2 cm3 1 2

Sizesmall

Tiny and ideal for nano tanks

Charming midwater shoaling behaviour

Very peaceful

1 2

Looks how to spot one

Armoured catfish (bony plates, no scales)

One of the tiniest catfish in the hobby. The slim, silvery body carries an unbroken black stripe along the middle of each side, a second thin line lower down toward the tail, and a dusky grey back. Females are a little larger and plumper than males. Newly hatched babies have vertical bars that fade within about a month.2 1

Colourssilverblack lateral stripedark grey back2 1

Personality what they are like

Very gentle and a little timid. Unlike most corys it often hovers and swims in loose shoals in the middle of the tank, not just on the floor. It is easily intimidated by large or boisterous tankmates, so it suits calm setups with other small fish.1 2

Daily activity how busy a day looks

Active and constantly on the move, mixing midwater shoaling with grazing on the bottom.1 2

Grooming and care the hands-on bits

Keep the water clean and stable with regular partial changes. A fine sand or smooth substrate suits its small barbels.1

Home where they are happiest

Minimum footprint of about 45 x 30 cm (around 41 litres) for a group. Water 22 to 26 C, pH about 6.0 to 8.0, soft water preferred (below about 8 dGH, though FishBase lists 2 to 25 dH). Planted tanks with open swimming space suit it well.1 3

Food basics what goes in the bowl

Small dried foods, crushed if needed, plus tiny live or frozen foods such as daphnia and baby brine shrimp, which also help bring out its colour.1

Company who they like around

A true shoaling fish: keep at least six, ideally ten or more.1 2

The story where it all began

The German aquarist Joachim Knaack described this species in 1966. For years it was often mixed up with the similar dwarf corydoras. In 2025 it was moved into the resurrected genus Gastrodermus.2 4

Fun facts for the dinner table

1
It is one of the smallest corydoras, with adults often only around 2 to 2.5 cm long.2
2
It is told apart from the look-alike dwarf corydoras by its full-length side stripe; the dwarf cory has a diamond-shaped spot at the tail instead.1
3
Baby pygmy corys hatch with vertical stripes that disappear within about a month.2
4
A female lays roughly 100 eggs per breeding cycle, carrying a few at a time between her pelvic fins.2

Recognised by the official bits

IUCN Red List: Least Concern (assessed 15 October 2020)3
Taxonomy: Placed in the resurrected genus Gastrodermus by the 2025 phylogenomic study of Dias, Tencatt, Roxo and colleagues4
Family: Callichthyidae (armoured catfishes), subfamily Corydoradinae2

The care rhythm a typical week and year

A typical home-care rhythm for a Pygmy Corydoras. A starting point, not a vet's advice.

FeedingSmall amounts once or twice a dayevery day
Temperature checkevery day
Water changeAbout 25% of the waterevery week
Water testevery week
Glass cleanevery week
Filter rinseRinse in old tank water, never tap waterevery month

Owner questions the things everyone asks

How often should I feed my Pygmy Corydoras?

Feed your Pygmy Corydoras small amounts once or twice a day. Furry Diary's starting plan is to feed daily, and you can adjust based on how much they eat in a couple of minutes.1 Pet Wiki plan

What does a Pygmy Corydoras eat, and what should it never eat?

They eat small dried foods, crushed if needed, plus tiny live or frozen foods like daphnia and baby brine shrimp. Avoid large or hard foods that could harm their tiny mouths, and never feed anything not meant for fish.1

How much space does a Pygmy Corydoras need?

A group needs a tank with a minimum footprint of about 45 x 30 cm, which is around 41 litres. This gives them room to shoal and swim comfortably.1 3

What temperature, light or water does a Pygmy Corydoras need?

Keep water temperature between 22 and 26°C, pH around 6.0 to 8.0, and soft water is preferred (below about 8 dGH). Planted tanks with open swimming space suit them well.1 3

How often should I clean a Pygmy Corydoras's home?

Furry Diary's starting plan suggests a weekly 25% water change, weekly glass cleaning, and a monthly filter rinse in old tank water. Regular cleaning keeps the water stable and healthy. Pet Wiki plan

Can a Pygmy Corydoras live with others?

Yes, they are very gentle and a little timid, so they do best with calm, small tankmates. They are true shoaling fish and should be kept in groups of at least six, ideally ten or more.1 2

How long does a Pygmy Corydoras live?

Lifespan varies depending on care and environment. For specific details, ask a good breeder or an exotic-pet vet.

Can I handle a Pygmy Corydoras?

It's best not to handle them as they are delicate and can be stressed. Always use a soft net if you need to move them, and keep handling to a minimum.1

Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.

Where this comes from

Every fact on this page has a numbered source. Spotted an error? [email protected].

Seriously Fish: Corydoras pygmaeus seriouslyfish.comused for care, size, behaviour, identification
Wikipedia: Pygmy corydoras en.wikipedia.orgused for description, colour, distribution, history, breeding
FishBase: Gastrodermus pygmaeus fishbase.seused for valid name, length, water parameters, IUCN status
Wikipedia: Gastrodermus en.wikipedia.orgused for 2025 genus revalidation

Checked 2026-09-30. Text is written in our own words from these sources.