Killifish are very closely related to many live bearers (Guppies, Mollies, Swordtails & Platies) even though they are edd layers. 

The species are often classed as annual fish as they are said to only live for one season, although most will live between 1 and 2 years. They have amazingly vibrant colours although it is mainly the males that exhibit the best coloration. Even though they do not live for very long, they are worth it for their beautiful displays. Many Killifish keepers enjoy the challenge of breeding them.