Pygmy Corydoras

Among Corydoras species, this one stands out for its miniature size: adults rarely grow larger than 3 cm. Outwardly, it differs somewhat from most of its relatives (not just in size), possessing a rather slender body and resembling more a typical fish that inhabits the water column. This observation is supported by the fact that the Pygmy Corydoras leads an active lifestyle, swimming throughout the entire volume of the aquarium, unlike many other catfishes that spend most of their time at the bottom. Its coloration is quite modest: a dark, grayish back and a light belly. Two noticeable wide light stripes run along its sides from the head to the tail. Its fins are transparent, with dark outlines of the rays.

The species inhabits South America, primarily in the Madeira River basin, as well as in tributaries of the Amazon, Aguarico, Napo, and Nanay rivers. In nature, it populates shallow areas of rivers, streams, and tributaries with slow currents. It prefers biotopes with soft sandy or silty substrate, abundant aquatic vegetation, driftwood, and fallen branches that create natural shelters. The water in these areas is usually soft and slightly acidic, often with the presence of tannins [practicalfishkeeping.co.uk].

A peaceful and active schooling fish. Unlike many other catfishes, it often spends time in the water column, moving in small groups. For comfortable well-being and to exhibit natural behavior, it is recommended to keep a school of 8–10 individuals. They are compatible with small, peaceful fish such as tetras, rasboras, or otocinclus. Keeping them with large or aggressive species is not permitted, as these may injure the corydoras or compete for food [aqvium.ru].

For a small group, an aquarium of 30–40 liters is required. Fine sand is essential as a substrate, as hard gravel can damage the fish's sensitive barbels. Live plants and shelters in the form of driftwood are necessary. Lighting should be subdued. Water parameters: temperature 22–26°C, pH 6.4–7.4, general hardness up to 15 dGH. Weekly water changes of 20–25% and filtration that creates a weak current are required [aquamir-za-steklom.com.ua].

An omnivorous species. In the aquarium, they accept any high-quality sinking foods: specialized tablets for bottom feeders, granules, as well as finely chopped live or frozen foods such as Artemia, Daphnia, or tubifex. The particle size of the food should match the fish's small mouth. Feeding should be done twice a day in small portions, ensuring that the food reaches the bottom and is not left uneaten [aquamir-za-steklom.com.ua].

Spawning is paired or in groups, often stimulated by water changes with cooler, fresh water. The female lays eggs on plant leaves or the aquarium glass. After spawning, it is recommended to remove the parents to prevent them from eating the eggs. Egg development lasts 4–5 days. Infusoria, microworms, and Artemia nauplii serve as initial food for the fry. Fish reach sexual maturity at 6–8 months of age [aquaristics.ru].

The species is sensitive to water quality, especially to the accumulation of organic waste. Under poor keeping conditions, bacterial infections affecting fins and skin may occur. It is important to maintain stable water parameters and avoid overfeeding. Like other armored catfishes, these fish have the ability to breathe intestinally, so access to the water surface must be unobstructed [aquamir-za-steklom.com.ua].

When purchasing, choose active fish with clean fins and no spots, sores, or film on their bodies. It is important to pay attention to the condition of their barbels — they should be intact and undamaged. It is preferable to acquire individuals that exhibit schooling behavior and actively search for food at the bottom. Avoid fish with sunken bellies or signs of apathy, as this may indicate emaciation or hidden diseases [practicalfishkeeping.co.uk].