Little Corydoras
Corydoras nanus
Callichthyidae
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About
A genuinely miniature armoured catfish from sandy forest creeks in the Suriname and Maroni basins of Suriname and the Iracoubo basin in French Guiana. It has the slim, elegant build of the elegans group, a dark lateral stripe edged above and below by paler lines, and usually a black bar at the base of the dorsal fin. Unlike the pygmy cory it is a committed bottom-dweller rather than a midwater hoverer, spending the day sifting sand shoulder to shoulder with its group and dashing to the surface now and then for a gulp of air. The true species is only rarely imported, so many shop fish labelled 'nanus' are look-alikes from the elegans complex.
Care
Keep six or more over soft sand in a tank of at least 60 litres and 60 cm of length, in soft to neutral water at 22-26 C that is kept pristine and well oxygenated. Furnish with driftwood, leaf litter and shaded planting but leave an open sand patch free for foraging, and keep the flow gentle to moderate. Sharp or chipped gravel wears the barbels away and must be avoided; a lid matters because this air-breather bolts to the surface.
Diet
Offer sinking micro-pellets, fine granules or catfish tablets as the staple, supplemented several times a week with small frozen or live foods: baby brine shrimp, Daphnia, cyclops, grindal worm and finely chopped bloodworm. An occasional vegetable or spirulina wafer rounds out the diet. Feed small amounts once or twice a day so the food actually reaches the bottom instead of rotting in the sand, and never assume it will live off leftovers - a cory is not a cleaner.
Tankmate compatibility
Gets along with (72)
Possible with care (100)
Avoid (99)
Computed by the AquaSage engine for a spacious reference tank — always check the full verdict for your exact setup in the calculator.
Telling males from females
What works for this species, most reliable first.
- Width from aboveStrong · from about 8 months, once they are adult-sized
Corydoras are sexed from directly above, never from the side. Look down at the group while they rest on the sand.
- Bristles and cheek spinesA hint only · from about a year
Male plecos grow odontodes — spiny growths on the cheeks and along the leading pectoral rays. Bristlenose males additionally grow branching tentacles across the snout and over the top of the head.
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Frequently asked questions
- What tank size does a Little Corydoras need?
- A Little Corydoras needs an aquarium of at least 60 litres (15.9 US gallons) with a footprint at least 60 cm (23.6 in) long — for this species, swimming length matters as much as raw volume.
- What water parameters does a Little Corydoras need?
- Little Corydoras does best at 22–26 °C (71.6–78.8 °F), pH 6–7.5 and a general hardness of 2–14 °dGH.
- What group size does a Little Corydoras need?
- Little Corydoras is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.
- Is the Little Corydoras suitable for beginners?
- Little Corydoras sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.