Pygmy Corydoras

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.21

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.12

Daily activity how busy a day looks

Active and constantly on the move, mixing midwater shoaling with grazing on the bottom.12

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.13

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.12

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.24

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