Pygmy Cory - Corydoras pygmaeus

The Pygmy Cory (Corydoras pygmaeus) is, as its name suggests, much smaller than other Corydoras catfish. Females reach about one inch in length at maturity; males are slightly smaller and usually more streamlined. It is a grayish fish with a single black horizontal stripe that runs from the tip of the snout to the middle of the tail. Its tiny size makes it vulnerable to larger fish, so it should only be kept in tropical community aquariums inhabited by small to medium, peaceful fish.

The small catfish from the genus Corydoras are often referred to collectively as the "Cory Cats". This genus has well over 100 members, all coming from South America and ranging in size from under 1 inch to up to around 3 inches in length as adults.

Cory cats are schooling fish, and should be kept in groups of at least 3-5 fish or more. Temperature should be monitored closely as Cory cats get easily stressed by cooler temperatures. They are also sensitive to stress and water quality. Monitor conditions closely as improper pH or high ammonia, nitrite or nitrate levels especially can be very harmful to Cory cats.

Corydoras catfish are found in some environments with low oxygen levels. To cope with this, they have adapted to take gulps of atmospheric air, absorbing the oxygen through their intestines and discharging the rest. It is normal to see them occasionally swim to the top, take a "breath" from the surface and return to the bottom. If they are doing this very often, however, check the water quality and make sure the oxygen isn't being depleted as a result of high temperature, high ammonia or nitrites, poor circulation or another condition.

Corydoras are peaceful and can be kept in most community and planted aquariums with fish like tetras, danios, rasboras, livebearers and rainbows. Provide broad-leaf plants and crevices under rocks or other ornaments for hiding places as well as some open areas for swimming room. Avoid substrate with sharp or jagged edges that can irritate and damage their undersides and barbels; fine or sandy substrates are best. They accept flake and small pellet foods as well as tablets, live or frozen worms, and brine shrimp.