Blue Corydoras Care Guide - Aquarium Setup, Diet & Breeding

Blue Corydoras are small, armoured catfish with a rounded body, an upturned mouth and sensitive barbels used to search the bottom for food. Their name refers to the attractive blue-grey sheen that can appear across the flanks, usually combined with darker markings and a pale underside. Like other Corydoras, they possess overlapping bony plates rather than conventional scales and can produce a mild defensive toxin when severely stressed.

These peaceful catfish are active, sociable and most entertaining when kept in a proper group. They spend much of the day exploring the substrate, briefly resting among plants or decor before suddenly becoming active again. They are not strictly nocturnal, so a settled group often remains visible during daylight hours.

In the wild, Blue Corydoras inhabit shallow, slow-moving streams, small rivers and flooded margins where leaf litter, submerged vegetation and soft sediments provide cover and feeding areas. Their barbels are adapted for locating tiny food organisms among the substrate, while their ability to gulp air at the surface helps them tolerate periodically oxygen-poor conditions.

Corydoras nattereri is a relatively uncommon species in the aquarium hobby compared with some of its better-known relatives. It is valued for its attractive bluish colouration, gentle temperament and natural bottom-dwelling behaviour, making a group a lively feature of a peaceful South American community aquarium.

Corydoras nattereri is native to coastal freshwater habitats in southeastern Brazil, particularly river systems in the states of Rio de Janeiro and São Paulo. It comes from the diverse South American watersheds of the Atlantic coastal region.

A group of Blue Corydoras should be kept in an aquarium of at least 75 litres, with a footprint of around 60 x 30 cm or larger; a longer tank is preferable because floor area matters more than height. Use fine smooth sand or another rounded, non-abrasive substrate so their delicate barbels are not damaged while foraging. Include hardy plants, driftwood, smooth stones and shaded retreats, while leaving open areas for group activity. Gentle-to-moderate water movement, good oxygenation and efficient filtration suit their stream-dwelling nature, but strong currents should not make the bottom difficult to navigate.

Up to approximately 5.5 cm (2.2 inches) in total length. Females are generally larger and broader-bodied than males; males usually reach about 4.5–5 cm (1.8–2 inches).

Blue Corydoras are omnivorous bottom-feeders that should receive a varied diet rather than relying on leftover food. Offer sinking catfish pellets or wafers, supplemented with frozen or live foods such as bloodworm, daphnia, brine shrimp and small insect larvae. Occasional blanched vegetables can add variety, although animal-based foods are especially useful for conditioning and growth. Feed enough for the whole group to find food, and do not assume that they can thrive on scraps from midwater fish.

Blue Corydoras are peaceful community fish and can be kept with similarly calm species such as small tetras, rasboras, pencilfish, peaceful danios, small livebearers and other non-aggressive Corydoras. They also coexist well with gentle dwarf cichlids, provided there is enough floor space and cover. Avoid large or predatory fish, fin-nipping species, aggressive cichlids and boisterous bottom dwellers that may outcompete or injure them. They should not be kept with fish that treat small catfish as prey.

Blue Corydoras are egg-scattering fish that can be bred in a mature aquarium. Condition a group with plenty of high-quality foods, including frozen or live offerings, then encourage spawning with a substantial water change using slightly cooler, clean water. The female carries a few adhesive eggs between her pelvic fins before placing them on aquarium glass, plant leaves or other smooth surfaces, while several males fertilise them. Remove the adults or transfer the eggs to a separate container, as the eggs and newly hatched fry may be eaten. The eggs usually hatch in around three to five days, and the fry can be raised on finely powdered food and newly hatched brine shrimp.

Females are typically larger, deeper-bodied and noticeably fuller when viewed from above, while males are smaller and more slender. The differences become most apparent when the fish are mature and in breeding condition.