Corydoras schwartzi

Corydoras schwartzi is a small bottom-dwelling fish with characteristic coloration: its body is light, covered with numerous small dark spots, and a distinct black stripe passes through its eye. A row of larger spots is often visible along the lateral line. The fish has sensitive barbels that help it search for food in the substrate. Sexual dimorphism is pronounced: females are larger and more robust than males, especially during spawning, while males are more slender and have slightly more developed pectoral fins.

The species is endemic to Brazil, inhabiting the Purus River basin. These fish live in areas of rivers with slow currents, where the bottom is covered with soft sand or silt, and the banks are densely vegetated. In their natural environment, they prefer places with abundant shelters in the form of snags and fallen leaves, which create shaded areas and provide protection.

This is a peaceful and schooling species that feels most comfortable in a group of 6 or more individuals. When alone, the fish become timid and less active. Corydoras schwartzi are primarily bottom-dwelling, constantly sifting through the substrate in search of food. They get along well with any calm, small fish that inhabit the middle and upper water layers and do not show aggression towards their tankmates.

For keeping a school, an aquarium of 70–100 L or more with a large bottom area is necessary. It is critically important to use a soft substrate (sand or fine rounded gravel) to avoid damaging the fish's sensitive barbels. The aquarium should include live plants, driftwood, and caves to create hiding places. It is recommended to maintain stable water parameters: pH 6.0–7.5 and a temperature of 22–26°C. Effective filtration and regular partial water changes are essential.

An omnivorous species, it feeds on small invertebrates, insect larvae, and plant detritus in nature. In the aquarium, they readily eat high-quality sinking foods: granules, tablets for bottom-dwellers, as well as frozen or live foods (brine shrimp, bloodworms). Feeding should be done in the evening when the fish's activity increases, allowing them to collect food from the bottom before other inhabitants eat it.

Breeding occurs through spawning. A stimulus for spawning is often a partial water change with cooler water, mimicking the rainy season. The female holds the eggs between her pelvic fins while the male fertilizes them, after which the pair deposits the eggs on a substrate — plant leaves or the aquarium glass. The parents do not care for their offspring. Fry begin swimming after a few days and require feeding with micro-foods.

These fish are susceptible to typical Corydoras diseases that arise from poor keeping conditions. The most common issues are barbel erosion due to sharp or dirty substrate, as well as fungal and bacterial skin infections when organic levels in the water are high. Prevention includes maintaining a clean bottom, using a soft substrate, and regular water quality monitoring.

When purchasing, choose active fish with clean skin and intact fins. It is important to ensure that the individuals' barbels are not damaged — their absence is a sign of improper keeping or illness. Avoid fish with sunken bellies or signs of lethargy. It is advisable to acquire a group of several individuals at once, as they adapt more quickly to new conditions and are less stressed in a school.