Bronze corydoras, Emerald green cory (Corydoras aeneus) care guide

Group
Freshwater fish
Other names
Bronze corydoras, Bronze catfish, Green corydoras, Green cory, Lightspot corydoras, Albino cory
Family
Callichthyidae (armoured catfishes)
Origin
Widespread in South America east of the Andes, from Colombia and Trinidad south to the Río de la Plata basin; probably a complex of several similar species.
Water
freshwater
Maximum size
7.5 cm
Temperature
21–27°C
pH
6–8
Hardness
Soft to medium-hard, 2–15 dGH
Minimum tank
72 litres
Care level
beginner
Temperament
peaceful

Care

The bronze cory is probably the most widely kept Corydoras of all and a great first catfish. It is gregarious, so keep a group of at least 6, ideally more of the one species, and it will spend the day shuffling about together over the bottom. Since the 2024 revision of the armoured catfishes it is called Osteogaster aenea (the name used by FishBase and Wikipedia), but it is still sold almost everywhere as "Corydoras aeneus"; Seriously Fish still lists it under that name. A tank with a base of about 80 × 30 cm (around 72 litres) suits a group. Use soft sand, or smooth rounded fine gravel, so the fish can sift without damaging their barbels, and keep the substrate clean as dirty, sharp gravel quickly erodes them. Plants, driftwood and a few shaded places are appreciated, with open sand for feeding. It is very adaptable: around 21–27 °C, pH 6–8 and soft to fairly hard water all suit captive-bred fish. Like other corys it gulps air at the surface now and then; this is normal. Keep nitrate low with regular partial water changes, avoid salt, and be careful with medications, especially copper-based ones, which corys tolerate poorly. The pectoral fin spines are sharp and mildly venomous and can catch in nets, so lift fish in a container if you can. Typical fish have a yellowish to pinkish body, a white belly and a blue-grey to greenish-bronze sheen over the head and back, usually with a brownish-orange patch in front of the dorsal fin. Albino (pale pink or orange with red eyes) and long-finned strains are very common and are the same species. Almost all bronze corys in the trade are farmed in large numbers; the natural range is so huge that scientists think "bronze cory" is really a group of look-alike species, and names such as C. schultzei and C. venezuelanus are often misapplied to particular trade forms. Well-kept fish can live around 10 years. FishBase lists it as Least Concern on the IUCN Red List. Sources: Seriously Fish (seriouslyfish.com/species/corydoras-aeneus/); FishBase (fishbase.se/summary/Corydoras-aeneus.html); Wikipedia (en.wikipedia.org/wiki/Bronzecorydoras). Checked October 2026.

Diet

A busy foraging omnivore. Feed a good-quality sinking pellet or tablet as the staple and add live or frozen bloodworm, Daphnia, brine shrimp and similar small foods regularly. It should be fed properly in its own right, not expected to survive on what other fish leave behind; feed after lights-down if faster fish grab everything first.

Breeding

Easily bred and one of the first Corydoras most people spawn. Use roughly two males per female and condition them on plenty of live and frozen food; females become larger and much rounder. A 50–70% water change with water a few degrees cooler, along with stronger aeration and current, often triggers spawning, imitating the start of the rainy season. Pairs take up the familiar "T-position", after which the female carries a few eggs in her clasped pelvic fins and sticks them on the glass, plants or décor; this is repeated many times and a full spawning can come to around 100–200 eggs. Remove either the adults or the eggs, as the parents will eat them. Eggs hatch in about 3–4 days. Feed the fry on microworm and newly hatched brine shrimp once they have absorbed their yolk sacs, and keep the water very clean.

Compatibility and tank mates

Peaceful and gets on with almost any community fish that will not eat or harass it: tetras, rasboras, danios, peaceful barbs, livebearers, gouramis, dwarf cichlids and other peaceful catfish. Avoid large predatory or very boisterous cichlids and persistent fin-nippers.

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

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