The species in this regional group can be found around the Mediterranean from Spain in southern Europe west to Israel and back east from north Africa as far as Algeria. They are also found in the Middle East as far as the westernmost corner of India. They can be split into two types: The Aphanius-type which is now divided into eight genera and all of which have relatively short, deep bodies; and the Valencia genus which contains three species, all with longer pike-like bodies. If maintained correctly, they can live up to seven years, the larger species reaching 10 cm in length.
The majority of Eurasian killifish require fairly similar conditions: The water should be hard with a pH of 7.5 – 8, which can be achieved using bicarbonate of soda at a third of a teaspoon per gallon and marine salt at one and a half teaspoons per gallon (with some exceptions that require more). A piece of tufa rock will also help to maintain the hardness (a fist-sized piece will suffice in a 10 gallon container). The aquaria should be furnished with filamentous algae and fine leaved plants (acrylic mops can also be added, though the fish tend to spawn in the algae given the choice). As these are seasonal fish, they should be kept in unheated aquaria allowed to drop to lower temperatures during the winter (down to 10°C or lower) so that they are triggered to spawn when the temperature rises in the spring and summer. Plenty of natural sunlight is also beneficial and helps keep the algae in full bloom.
Eggs are fairly easy to find, particularly by touch, running the algae through your fingers under water. They hatch in around 14-21 days and can eat newly hatched brine shrimp and powdered dried food straight away, though the algae also provides minute organisms for them to feed on. If the aquarium has heavy algae and plant growth, it is possible for the fry to grow on with their parents in some cases, though it may be advisable to remove fry and eggs for safety and place them in separate rearing containers (floating these in the adults’ aquarium is the best option).
Some of the more popular species
Aphanius fasciatus – found extensively around the Mediterranean clockwise from Corsica and Italy to Tunisia (some populations may be redesignated under new genera). Most populations live in coastal lagoons and require a high salt content in their water (five teaspoons per gallon).
Anatolichthys danfordii – found in only one location in central Turkey. This is one of the few species which doesn’t require salt and prefers neutral water at pH 7.
Apricaphanius iberus – found in southern Spain in coastal rivers and wetlands.
Apricaphanius iberus ‘Peniscola’
Apricaphanius baeticus ‘Cabezas de San Juan’
Paraphanius similis – found in southern Turkey in coastal rivers and wetlands.
Esmaeileus vladykovi – found only in a couple of highland valley wetland locations in southwest Iran.
Aphaniops dispar – found in a number of locations around the Red Sea.
Valencia letourneuxi – found in a few locations in northwest Greece, including Corfu, and southwest Albania.