corydoras catfish, rare and timid freshwater species from acidic blackwater habitats, swim in biotope aqua

acidic adult amazon america animal aqua aquarium aquatic balance barbel biological biotope blackwater bottomdweller callichthyidae captive care catfish clear closeup conditions controlled corydoradinae corydoras decorative design diversity easy eco eques fauna fin fish fishkeeping free freshwater gravel habitats instinct little low macro nano native natural nature ornamental peaceful pet popular rare river south species stream swim tank timid underwater vulnerable water