Killifish, with the exception of the pike killie, are smaller species and adaptable to planted and community fish tanks. Male killifish have more color and so these fish are easy to sex. Most killifish, also known as panchax fish, are jumpers. Clown killie are a bit too small to jump from the tank but most are not so a cover is required.
Killi is Dutch for small stream and their jumping ability enables them to move from one body of shallow water to another.
The smallest killifish aquariumfishsale offers are the Norman's lamp-eye killi and the clown killi, popular for bright color markings. American flag fish killi are popular for their great algae eating skills.