Corydoras nanus is a tropical freshwater

Freshwater

Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 belonging to the Corydoradinae sub-family of the Callichthyidae

Callichthyidae

Callichthyidae is a family of catfishes , called armored catfishes due to the two rows of bony plates running down the length of the body. This family contains some of the most popular freshwater aquarium fish, such as the Corydoras.-Taxonomy:The family derives its name from the Greek words kallis...

 family. It originates in inland waters in South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, and is found in the Suriname

Suriname River

The Suriname River is 480 km long and flows through the country Suriname. Its sources are located in the Guiana Highlands on the border between the Wilhelmina Mountains and the Eilerts de Haan Mountains...

 and Maroni River

Maroni River

The Maroni or Marowijne is a river in South America. It originates in the Tumuk Humak Mountains and forms the border between French Guiana and Suriname...

 basins in Suriname

Suriname

Suriname , officially the Republic of Suriname , is a country in northern South America. It borders French Guiana to the east, Guyana to the west, Brazil to the south, and on the north by the Atlantic Ocean. Suriname was a former colony of the British and of the Dutch, and was previously known as...

 and the Iracoubo River basin in French Guiana

French Guiana

French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...

. It was originally described by H. Nijssen

Han Nijssen

Han Nijssen is a Dutch ichthyologist. He is curator at Zoölogisch Museum in Amsterdam.Nijssen has worked extensively with fish from South America, and is the author of several species, e.g. Corydoras weitzmani and Corydoras xinguensis....

 and I. J. H. Isbrücker in 1967.

This fish has been found in creeks with a moderate current, 0.5 to 3 m wide, shallow (20 cm to 50 cm depth) with sandy to sandy-muddy bottom and not brightly illuminated. It will grow in length up to 1.7 inches (4.5 centimeters). It lives in a tropical climate in water with a 6.0 - 8.0 pH

PH

In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

, a water hardness of 2 - 25 dGH

DGH

Degrees of general hardness is a unit of water hardness, specifically of general hardness.General hardness is a measure of the concentration of metal divalent ions such as calcium and magnesium per volume of water...

, and a temperature range of 72 - 79 °F (22 - 26 °C). It feeds on worm

Worm

The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...

s, benthic crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s, insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s, and plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

matter. It lays eggs in dense vegetation and adults do not guard the eggs. In captivity, eggs have been deposited mostly on plant leaves. The female may produce up to 600 eggs.

Corydoras nanus is of commercial importance in the aquarium trade industry.