The Killifish is a name given to many different types of oviparous (egg laying) cyprinodontiform fish. The origin of the name is uncertain, but it is believed to come from the Dutch for a 'kill' ('kill' meaning a body of water). There are over 1250 different species of Killifish! The largest family, within the species, is the Rivulidae which contains over 320 different species! Most of the species live in ephemeral waters and their eggs can therefore survive periods of partial dehydration. Due to this fact, most Killifish eggs can be sent through the mail without being submerged in water! Some species, such as the Kryptolebias, can actually survive out of water for several weeks! Killifish are mainly found in fresh or brackish waters in the Americas, Europe and Africa. The most common place to find a wild Killifish is in a permanent stream, river or lake.

Before purchasing any fish it is important to understand that as a fish owner you are responsible for the care and wellbeing of your fish. It is important to try and learn as much as you can about the fish you are considering to keep. You need to make sure that your lifestyle, household and financial status are suited to provide your fish with the best possible care. This guide has been designed to provide you with both precise and concise information about a Killifish's basic needs to help you provide your fish with the best quality care and aquarium practices. This guide also goes into the benefits of cycling, having a decent filtration system, plants and how to plant them.