Dwarf Corydoras

The dwarf corydoras is the smallest of its kind, reaching barely 3.5 cm. A tiny armoured catfish in the family Callichthyidae, it carries a translucent silvery-grey body traced by a dark lateral line that ends in a black diamond-shaped spot on the tail, ringed with white. A recent phylogenomic revision moved it to the genus Gastrodermus. It ranges across the Amazon and Paraguay basins, from Brazil through Bolivia and Paraguay to north-eastern Argentina. Collectors find it in marginal channels, backwaters, swamps, floodplain lakes and small tributaries — shallow, clear to turbid water over mud and clay, sometimes bare, sometimes thick with submerged grasses and floating plants. Unlike its bottom-sifting cousins, it swims in open water in a tight shoal: keep at least eight, ideally ten or more. A 60 cm footprint is the floor — despite its size, this species is unsuited to nano tanks. Fine sand, roots and floating plants give it confidence, while live daphnia and brine shrimp keep it in condition. Too small to compete, it fades away alongside larger or busier fish.