All armoured catfish in the families Aspidoras, Brochis and Corydoras come from mainland South America and one island (Trinidad, and then only C. aeneus). The map below shows the approximate altitudes of the area. The black line shows the approximate western and southern limits for this group of fish.

The fish are mostly found in the lowlands, below 500 m (1700 ft), where the water temperature easily can reach over 30°C (86°F) in the dry season. Some are found in higher areas, such as C. barbatus and macropterus, in the highlands in the east around São Paolo.

Many species also come from the small rivers close to the Andes (i.e. C. metae, napoensis, panda, reynoldsi, and stenocephalus). During the rainy season the water temperature in the highlands and in waters near the Andean slopes drops to well below 15°C (59°F) in many rivers.

Some species (C. paleatus and undulatus) come from the southern parts, Uruguay and central Argentina, a temperate climate. During the winter the air temperature can temporarily drop to below 0°C (32°F) and ponds be ice-covered!

I've been collecting in Uruguay during the spring and we measured as low as 13°C (55°F) in a small creek close to the coast. After one month the water temperature had risen 0.8°C! The creek was full of 1-2 month old C. paleatus fry of which some are still (2005) swimming in my tanks.

Even in Uruguay we caught fish in flooded grasslands where the temperature almost reached 30.