Rust corydoras (Corydoras rabauti) care guide

Group

Freshwater fish

Other names

Rabaut's cory, Rust cory, Rust corydoras, Iridescent cory, Rabaut's corydoras, Myers's corydoras, Orange-red corydoras, Rabaut's catfish

Family

Callichthyidae (armoured catfishes)

Origin

Upper Amazon, Solimões and Rio Negro basins; best known from the Rio Javarí on the Brazil–Peru border. Lives in floodplain lakes, oxbows and rivers in Brazil and Peru, possibly Colombia.

Water

freshwater

Maximum size

6.5 cm

Temperature

20–27°C

pH

5.5–7.2

Hardness

Soft to medium, 1–12 dGH

Minimum tank

81 litres

Care level

beginner

Temperament

peaceful

Care

The rusty cory is a sociable, active shoaling catfish and should be kept in a group of at least 6 of its own kind, and ideally more – a bigger group behaves more naturally and is far more confident. It is one of the larger, more energetic corys, so give it a tank with a base of at least 90 × 30 cm (around 81 litres) with plenty of open floor space for the group to forage together. Like all corys it spends its life on the bottom, sifting through the substrate with its barbels for food, so fine sand is by far the best choice. Smooth, rounded gravel can work if it is kept spotlessly clean, but sharp or dirty substrate wears the barbels down and lets infections in. Add some driftwood, a few smooth rocks and plants to give the fish cover, and leave open stretches of sand in front. It is a hardy, adaptable fish. Aim for about 20–27 °C, a pH of roughly 5.5–7.2 and soft to moderately hard water (up to about 12 dGH), with good filtration and some water movement. Add it only to a mature, stable tank. Corys have no scales, only bony plates, and are sensitive to salt and to many medications (especially copper-based treatments), so use half doses or leave them out when treating a tank. Keep nitrate low with regular partial water changes and siphon the sand surface lightly so uneaten food does not rot. They are facultative air breathers and will dart to the surface now and then to gulp air, which is normal. Take care when netting them: the pectoral-fin spines are sharp, can pierce skin and lock into nets, and the glands at their base may release a mildly toxic secretion. Since the 2024 revision of the corydoradine catfishes (Dita and colleagues) this species has been placed in the genus Osteogaster, but it is still widely sold as "Corydoras rabauti", and older books may also call it Corydoras myersi. Adults are a warm rusty-orange with a dark band running back along the upper flanks. It is easily confused with Corydoras zygatus; in the rusty cory the dark band dips down onto the lower part of the tail stalk, whereas in C. zygatus it stays along the top. An albino form is also sold. It is regularly seen in the aquarium trade. FishBase lists it as Least Concern on the IUCN Red List (assessed 2020), although Wikipedia describes it as not evaluated. Sources: Seriously Fish (seriouslyfish.com/species/osteogaster-rabauti/); FishBase (fishbase.se/summary/Corydoras-rabauti.html); Wikipedia (en.wikipedia.org/wiki/Osteogasterrabauti). Checked October 2026.

Diet

A foraging omnivore that eats small worms, crustaceans, insects, detritus and plant matter in the wild. Feed good sinking pellets or wafers as the staple, with regular small live or frozen foods such as bloodworm, brine shrimp and Tubifex. Make sure food actually reaches the bottom – corys should never be left to live on other fishes’ leftovers.

Breeding

Females grow larger than males and become noticeably broader and deeper-bodied when mature. Use two or more males for each female and condition the group well on live and frozen foods. A large (50–70%) water change with slightly cooler water, plus extra aeration and flow, often triggers spawning. The female holds a few eggs at a time between her pelvic fins while a male fertilises them, then sticks them to the glass, plants or spawning mops; a pair repeats this until up to about 100 eggs have been laid. The adults give no care, so move the eggs or the adults afterwards. Eggs hatch in 3–4 days. Once the yolk sacs are used up, feed the fry microworm and newly hatched brine shrimp. The fry need excellent water quality and grow on best over a thin layer of sand.

Compatibility and tank mates

Peaceful and gregarious, and a good community fish. Keep with other calm, small to medium fish such as tetras, rasboras, pencilfish, small gouramis, dwarf cichlids and other peaceful catfish. Avoid large or aggressive species and anything that will outcompete it for food on the bottom.

Last updated 4 October 2026. Community-edited care guide on Aquatic-Auctions.