Killifish are very closely related to many live bearers (Guppies, Mollies, Swordtails & Platies) even though they are egg 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. Many Killifish keepers enjoy the challenge of breeding them.