Aphanius apodus
Classification
Cyprinodontidae
Distribution
Endemic to a small region of the Tellian Atlas mountains in northeastern Algeria, between the cities of Constantine and Batna. The last collection of the species was in 1990 with ongoing political instability in the country limiting access in the years since.
Current distribution is therefore uncertain with rumours suggesting that it‘s already extinct due to the introduction of highly invasive Gambusia affinis and pollution of habitats through agriculture. All of the fish currently in the hobby should be of a population that existed at Aïn M‘Lila in Oum El Bouaghi Province, just south of Constantine.
Habitat
Little information is available but likely to inhabit streams, springs and ponds with growths of aquatic vegetation and/or filamentous algae.
Maximum Standard Length
Aquarium SizeTop ↑
A pair or trio can be kept in a container with base dimensions of 60 cm x 30 cm or so but as a general rule members of this genus do better when maintained as a larger group in a space measuring upwards of [dimensions].
Maintenance
Even for long–term maintenance a simple set–up will suffice. The most important factors are the provision of cover and a suitable medium in which the fish can deposit eggs. Much of the available space can therefore be filled with acrylic wool mops (use a fine grade if available) and ideally filamentous algae. Fine–leaved plants such as Java moss or Ceratophyllum can be used but may fail to thrive as the addition of marine salt to the water in the ratio of 1–2 g/L is recommended.
Similarly, there‘s no need to add a substrate although inert sand or gravel can be used if you prefer and filtration need not be too strong either. It is possible, and preferable, to maintain it outdoors all year round in many countries and it will show better colours and overall condition if exposed to at least a few hours of natural sunlight each day. There is no real need to use an aquarium in this case and we keep our Aphanius outdoors in large plastic storage containers.
Water Conditions
Temperature: Active over a wide temperature range of [temp]. It should be provided with a ‘winter‘ period of several months during which it is maintained at temperatures towards the lower end of this range or it is likely to suffer both reduced fecundity and a shortened lifespan.
pH: [pH]. It will probably not survive under acidic conditions.
Diet
Aphanius species are basically micropredators feeding on small aquatic crustaceans, worms, insect larvae and other zooplankton although algae and other plant material is also taken at times. In the aquarium they will learn to accept dried foods in most cases but should also be offered regular meals of small live or frozen fare such as Artemia, Daphnia or bloodworm. This is particularly important during the months of spring and summer due to their high reproductive effort throughout this period. If the aquarium or container does not contain filamentous algae try to introduce a good quality dried product with added Spirulina content to the diet.
Behaviour and CompatibilityTop ↑
Given its particular water requirements and precarious conservation status we strongly recommend maintaining it alone, the emphasis being on captive reproduction. Ideally it should be kept in a group with a ratio of two or three females to each male. Males are not as aggressive as those of most congenerics and several can usually be maintained together without problems.
Sexual Dimorphism
As with all members of the genus sexual dimorphism is pronounced. Males exhibit a body pattern consisting of a yellow belly with 6–8 vertical bars giving way to small, irregularly–distributed, iridescent spots towards the caudal peduncle. The dorsal, anal and caudal fins also possess iridophores at the base merging into a thick, dark stripe with a yellow distal band. Females are larger and much plainer possessing only a series of variable dark blotches on the flanks and completely hyaline finnage.
Reproduction
Captive reproduction is not difficult if the tank or container is properly arranged and maintained (see ‘tank set–up‘). It is a fractional spawner with females depositing eggs on a more–or–less continuous basis between the months of April and September. Males form temporary territories which they defend against rivals while attempting to entice females to spawn. Dominant individuals will show more intense colouration. Eggs are released singly or in small batches and are attached to algae or other surfaces by means of small filaments. Aphanius typically eat their eggs/fry and the medium should therefore be checked on a daily basis during the spawning period.
The eggs are very small and must be treated carefully. Use a fine pair of forceps to gently remove pieces of medium with eggs attached whilst avoiding contact with the eggs themselves. Alternatively the entire medium can be removed and replaced every couple of days. The medium/eggs should be transferred to a container with water of the same chemistry and temperature as that of the adults. The incubation period can vary a little with the temperature but is usually between 7 –14 days with the fry being large enough to accept Artemia nauplii, microworm etc. immediately after they become free–swimming.
NotesTop ↑
The genus Aphanius currently contains 22 species and subspecies which are thought to have derived from a common ancestor originally distributed around the periphery of the former Tethys Sea. These can be separated into two main phylogenetic groups usually referred to as the ‘eastern‘ and ‘western‘ clades by scientists and aquarists because they broadly correspond to those coastlines of the Tethys. The eastern clade comprises the species now found in the Arabian Peninsula and in coastal parts of countries to either side of it from Somalia in the east to Pakistan in the west.
Members of the western clade occur in Turkey, Iran, the Iberian Peninsula and other coastal areas of the Mediterranean including north Africa. A few species are still listed as a species of Lebias by some sources although that name has long been considered a synonym of Cyprinodon by most authorities and an ICZN committee voted to suppress the name in favour of Aphanius as recently as 2003.
Among the western group A. apodus sits apart from the rest in genetic terms. Uniquely it lacks ventral fins and a 2003 phylogenetic study found it to represent a sister group not only to other western clade members but all other Aphanius in some tests. It is thought that this species occupies an unstable genetic position because of its relatively higher rate of molecular evolution compared to its relatives. A. iberus, A. baeticus and A. saourensis are its closest allies.
You‘re unlikely to find it on sale in aquatic stores although it may be available via specialist breeders or associations from time–to–time. While Aphanius are certainly not as colourful as some of their relatives their interesting behaviour and continuous activity make them fascinating aquarium subjects and well worth a try if you possess the dedication to take on a long–term maintenance project since conservation is key with all members of the genus.
References
- Blanco, J.L. 2004 - SEI/GEVA Ficha.
Aphanius apodus (Gervais, 1853). - Hrbek, T. and A. Meyer. 2003 - J. Evol. Biol. 16(1): 17-36.
Closing of the Tethys Sea and the phylogeny of Eurasian killifishes (Cyprinodontiformes: Cyprinodontidae).