Hardy fish is a term which refers to any fish which is easy to maintain in home aquaria due to their ability to adapt to a wide range of water parameters. Such fish are good starter fish and ideal for 'cycling' your aquarium (i.e. reducing ammonia and nitrites to effectively zero.)
Examples of hardy freshwater fish include Poecilids such as the guppy, betta, molly and platy, most species of Corydoras, zebra danio and some other tetras. Generally, fish are hardy only when they have been tank-bred, since wild-caught fish may take many generations to adapt to life in captivity.
