Killifish

You can pride yourself justifiably for having killifish in your possession. Unrivalled for their colour and easy maintenance, the killifish lead sweet but sadly short lives. The reason behind there short lives is a very interesting one.

Some of these fish inhabit temporary pools which form in the rainy season in Africa these pools only last for a few months of the year and then dry up completely. This obviously is a problem for any fish living there. To solve killifish fish have to hatch, mature and breed very quickly, the fertilised eggs then sink into the mud and remain there all through the dry season. The embryo carries on growing and developing even when there is no water present. The eggs develop right up to the point of hatching and then wait for the rain. They need a good long soak before they will begin to hatch, this prevents the Killifish from hatching to soon in case of a just after a small shower. If the worst came to worst and the pool didn't last long enough for them to breed there are some eggs which need to be soaked twice or even three times before they hatch, This has allowed killifish to live where no others can, but the price they pay for that is a shortened life.

Killifish as a group
comprise over 700 species from most regions of the world. As a group Killifish have one main drawback and that is that they tend to be short lived; some species are past their best at just 5 months old whilst other live to the ripe old age of about 2 years. This means that Killifish aren't commonly seen in the shops because once adult they don't have long left to live. To get around this the people who keep them also breed them ensuring a steady supply. Most of these fish will breed very easily in the aquarium although the eggs of some species do require quite a bit of after care and they can take an age to hatch.

Not all Killifish are annuals though, some live in permanent bodies of water and live much longer.

With just the odd rare exception Killifish do not form shoals and usually two males in the same tank will compete for dominance, because of this they are best kept in either pairs or trios with just a single male.

There are over 800 species and one of the most popular varieties is the Aphyosemion This is a very popular group of Killifish because they are colourful, hardy and easy to maintain. These fish are easy to breed and the eggs can be left with the parents and don't need to go through a dry spell in order to hatch. The adults have a strong preference for live food but if the fry are fed on flake food at an early age they will continue to eat it as adults making their maintenance much easier. Some species are fine in a community tank but others have a reputation for being aggressive