Killifish are oviparous and part of the Cyprinodontiformes order. There are over 1000 species of killifish that are found almost all over the world except in Australia and Antarctica. Hobbyists are attracted to these fish because of their beautiful colors and low maintenance. So, whether you plan to have a new addition to your aquarium or are just curious to know all about this fish, here are some facts.
Fascinating Killifish Facts
- There are three classes of killies: annuals, semi-annuals and non-annuals. The annuals hatch from eggs buried in the mud and live in ponds and swamps. They grow very fast and breed before the water dries. They live for 6-9 months. Semi-annuals can survive in both wet and dry conditions, their eggs can either be left to hatch, or they can be dried and hatched. They live 2-3 years when kept in cool conditions. If you keep them in warmer conditions, they will live for about a year. Non-annuals live in permanent water bodies and are the longest living killifish; they can live up to five years depending on the species.
- Most killifish are small, their size is about 2 to 3.5 inches. A few species, like the Blue Gularis grow up to six inches.
- They live in varied habitats, from seasonal streams and ponds to big lakes and oceans. If they are not comfortable in a habitat, they tend to hide. The reproductive process of the fish differs, depending on the environment where they live.
- Some killies create a nest and lay eggs there to protect it. Others simply spread their eggs on plants, while some others lay eggs inside crevices.
- Killies that live in seasonal water bodies have the most unusual reproductive and survival tactics. They drop their eggs deep in the mud. The eggshells are very tough. During the dry season, the adult fish do not survive, however the eggs remain buried and hatch once it starts raining.
- Killifish feed mainly on insects floating in the water, small worms and insect larvae. Some species feed on other fishes, while others feed on algae and other plants. In aquariums, live food such as mosquito larva, fruit flies, brine shrimp and worms are the best. However, frozen food of good quality also works well. Dry food may or may not be given; if your killies are used to live food, they may not eat dry food. Yet, others may take to dry food.
- Killifish live in small groups; a male fish usually lives with several female fish. One superior male safeguards his group from all other male killies. Male killies swim around the females chasing them to 'spawn'. The females hide behind plants and other shelters.
- It is easy to differentiate between the sexes of killifish. Males are usually bright, they can be yellow, blue, green and red while females are in dull colors like brown, and drab in comparison to the male.
- It has been found that in areas where there are no killifish, there is widespread malaria because, otherwise they feed on mosquito algae. They can also be useful to control algae in aquariums.
Breeding of Killifish
- Killies need acidic water for which the pH should be between 5.0 and 7.0; however, this depends on the species. Make sure, you get information on the water requirement for your species. The basic water requirement is to keep it clean at all times. A sponge filter can be used to keep the water clean.
- Killies love jumping and they will jump out of the tank, from any small space that they find. Hence aquarium owners, should be particularly careful to use a tight lid, or else you will find your killifish on the floor.
- Since most killies live in shallow ponds and swarms, the depth of the aquarium is not a cause of concern. They can breed in small tanks; a depth of about 6 inches is sufficient.
- Killifish should preferably be kept alone in a tank. Even though they are small in size, they can get aggressive and attack other fish, the male fish in particular can be very aggressive. The different species of the fish should not be mixed, to avoid clashes and interspecies breeding.
- Killies require a spawning mop to breed successfully in a tank, they use the mop to lay eggs. It is easy to make a mop at home. Take a dark acrylic yarn, boil it in water to get rid of any residue dye. Once the yarn is dry, take a book, wind the yarn across the length of the book, about a 100 times. Then, simply knot it somewhere in the middle. Next remove it from the book and cut on the opposite side of the knot. Next, tie a knot on the other end of the cut and make it like a ball. Do not tie the knot too hard, or else there will be no place for the eggs. Your killie mop is ready to be used.
These were some interesting facts about this beautiful breed of fish. Killies are easy to keep and breed, so just keep some of these killifish care instructions in mind and you will discover how easy it is to maintain this lovely breed of fish.