Not furry, but we like them anyway.
Dwarf Corydoras
Gastrodermus hastatus (Eigenmann & Eigenmann, 1888); long known as Corydoras hastatus
Also called Dwarf cory, Tail-spot pygmy cory, Tail spot pygmy catfish, Micro catfish, Dwarf catfish
From Widespread in South America: the Amazon and Paraguay River basins in Brazil, Bolivia, Paraguay and north-eastern Argentina, with reports from the upper Parana.123
At a glance the quick version
Looks how to spot one
Armoured catfish (bony plates, no scales)
A miniature, see-through looking cory with a body that ranges from translucent white to olive and a pale belly. A thin dark line runs along the side, and the tail base carries a black, spearhead-shaped spot framed by a white crescent. Males stay smaller and slimmer than the broader-bodied females.32
Personality what they are like
Peaceful and lively. Unlike most of its relatives it spends much of its time swimming in midwater among plants, with quick, fluttering fin movements, and it will happily shoal with small tetras.23
Daily activity how busy a day looks
Very active, shoaling through open water and plants rather than staying on the bottom.23
Grooming and care the hands-on bits
Keep the water clean and stable with regular partial changes, and offer dense planting as cover.23
Home where they are happiest
Minimum footprint of about 60 x 30 cm (around 54 litres) per Seriously Fish, though Wikipedia notes a school of six can live in a tank from about 19 litres (5 US gallons). Water roughly 20 to 28 C across sources, pH 6.0 to 8.0, hardness about 2 to 12 dGH. Plenty of plants are important.213
Food basics what goes in the bowl
Partly adapted to feeding on drifting zooplankton, so offer live daphnia and brine shrimp alongside frozen bloodworm and good small dry foods.2
Company who they like around
Keep in a group of at least four to six, ideally ten or more.2
The story where it all began
Carl and Rosa Eigenmann described the dwarf corydoras in 1888. It has long been a popular nano fish and was often confused with the pygmy corydoras. In 2025 it was moved to the resurrected genus Gastrodermus.314
Fun facts for the dinner table
- 1
The name hastatus means spear-bearing, after the spearhead-like spot at the base of the tail.3
- 2
In the wild it often shoals with small tetras that share a similar tail-spot pattern.2
- 3
Unlike typical corys, it lives mostly in midwater among plants rather than on the bottom.3
- 4
It can gulp air at the surface and absorb the oxygen through its gut.2
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed 3 February 2021)1
- Taxonomy
- Placed in the resurrected genus Gastrodermus by the 2025 phylogenomic study; Corydoras australe is a synonym4
- Family
- Callichthyidae (armoured catfishes), subfamily Corydoradinae1
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Dwarf Corydoras. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- 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
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- FishBase: Gastrodermus hastatus fishbase.seused for valid name, length, water parameters, IUCN status, distribution
- Seriously Fish: Corydoras hastatus seriouslyfish.comused for care, size, behaviour, diet, breeding
- Wikipedia: Dwarf corydoras en.wikipedia.orgused for description, colour, behaviour, etymology, tank size
- Wikipedia: Gastrodermus en.wikipedia.orgused for 2025 genus revalidation
Checked 2026-09-30. Text is written in our own words from these sources.