Killifish for this selling is Nothobranchiidae are a family of bony fishes containing roughly 300 killifish species. They are small killifish, usually measuring about 5 centimeters in length. Killifish Species are essentially limited to Africa. Killifish live in fresh water but are somewhat salt-tolerant. Killfish are also found in muddy or brackish water. Some killifish species are kept as aquarium pets. Killifish have frilly fins and many are brightly colored. Members of Killifish genus Nothobranchius are found in mud pools on the plains of Africa, a habitat shared by no other fish except the lungfishes. Killifish life cycle is only a year long, and they die when the pools dry up. Pools of this type are often sprayed with poison to reduce mosquito populations, which also kills the fish. Killifish Hatching Instruction As might be expected with short-lived species living in an ephemeral habit, many of these killifish reach sexual maturity within weeks of hatching, and are prolific breeders.