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Aphanius danfordii (BOULENGER, 1890)

Classification

Order: Cyprinodontiformes Family: Cyprinodontidae

Distribution

This species was described from “Asia Minor at Albistan” which should correspond to the town of Elbistan in Kahramanmaraş province, central Turkey. However in recent surveys only A. mento was found at this locality and its range appears to be restricted to parts of the middle to lower Kızıl river system as far north as its mouth at the Black Sea as well as the lower Yeşil river and the upper Seyhan drainage south of the city of Kayseri. 

In the latter it inhabits the Sultan Swamps (Sultan Sazlığı) close to Soysallı village, a RAMSAR site famed for its diversity of birdlife. In a 1999 paper on Turkish Aphanius Wildekamp et al. state that the original type locality should be regarded as “”Elbistan District”, in which the Sultan Swamps are located”. This is confusing as maps show the swamps actually cover parts of Develi, Yeşilhisar and Yahyalı districts in Kayseri province.

The colouration and patterning can vary somewhat depending on locality, especially in males, and the different forms are often labelled with the collection details by aquarists and scientists in order to preserve bloodlines and maintain accuracy e.g. ‘Soysallı’, ‘Kırşehir’, etc. 

Fish from the Sultan Swamps also possess a relatively straight dorsal fin profile and in phylogenetic studies have been shown to be genetically distinct, forming a monophyletic sister group to the Kızıl/Yeşil populations. Unfortunately the construction of an irrigation canal connecting Soysallı with the Kızıl has already resulted in hybridisation so it is likely that these distinguishing characters will now be lost.

Habitat

Inhabits springs, small streams, creeks and marshes, some of which are subject to seasonal fluctuations in water level. For example at Karpuzatan near Kayseri city it is found in a swamp which largely dries up in summer and results in a large annual decrease in population size. Unfortunately it is being outcompeted by introduced Gambusia affinis at this locality, a common problem for the species across some of its range. It is usually found in areas where filamentous algae or higher plants such as Ceratophyllum or Chara spp. proliferate.

Maximum Standard Length

45 – 50 mm.

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 ofthis 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 many broken lines of sight and a suitable medium in which the fish can deposit eggs. Female and subdominant male individuals must be offered the opportunity of respite from the aggressive alpha males during the spawning season so much of the available space can be filled with acrylic wool mops (use a fine grade if available), clumps of java moss or Ceratophyllum and ideally filamentous algae

There’s no need to add a substrate although inert sand or gravel can be added if you preferand 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.

Water Conditions

Temperature: Active over a wide temperature range of 10 – 30 °C. 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: Apparently it has been collected from waters with a pH of 6.4 but we still recommend maintaining it within the range 7.0 – 8.5.

.

Hardness: 179 – 536 ppm

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 ↑

Its particular water requirements and aggressive spawning behaviour make A. danfordii a poor choice for the community aquarium. Given its rarity in the hobby the emphasis should also be on captive reproduction and we strongly recommend maintaining it alone. It should be kept in a group with a ratio of two or three females to each male being the ideal.

Sexual Dimorphism

As with all members of the genus sexual dimorphism is pronounced. Males exhibit a series of 9-13 grey to black vertical bars in on the body with usually three dark bars in the caudal fin. The anal fin is yellow with 2-3 bars and a thin black edge and when in spawning condition the dorsal fin turns black with lighter spots at its base. Females are larger and much plainer possessing only a series of variable dark blotches on the flanks along with a roughly circular black marking on the caudal peduncle and, except for a pale brownish dorsal fin, 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 ↑

This species has something of a confused history having been previously been considered synonymous with both A. sophiae and A. fasciatus. Another species, A. chantrei is still listed as valid by some sources but is now known to be a junior synonym of A. danfordii. This became clear during a 1999 study in which the type specimens of A. danfordii were found to be indistinguishable from the Aphanius population living in the Sultan Swamps, the type locality of A. chantrei.

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.

Anatolia represents a centre of diversity with ten species endemic to the region. These are thought to have diverged as a result of the splitting of what was originally a vast lake covering much of modern Anatolia. Two separate divergence events occured, the first resulting in the western separation of A. asquamatus, A. danfordii and A. villwocki around 12-15 million years ago (possibly earlier in the case of A. asquamatus). 

Lakes Tuz, Eğirdir and Beyşehir are remnants of the central part of the lake where A. anatoliae now occurs and there exist three other locally endemic species in the Turkish Lakes region that were isolated when the eastern end of the lake became disconnected around 11-12 mya. These were further separated from one another 7-8 mya and have evolved independantly to survive in bitter lake environments containing high levels of alkaline carbonates and sulfates. 

Due to a historic lack of competition, predators and aquatic vegetation in their habitats they have developed distinctive limnetic (open water) characteristics including an elongated, relatively slim body shape and unique jaw morphology. A. danfordii is currently separated from these by a volcanic range at the eastern edge of the Lake Tuz basin.

The genus 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. None are particularly well-documented in aquarium literature although some are very beautiful and the majority are not too difficult to maintain and breed. Sadly most are on the verge of extinction for one reason or another with several existing only in remnant, highly-localised populations. 

In practically all cases the root cause for this decline is the activity of humans and although some species are now protected by conservation law the mismanagement and degradation of their habitats continues at an alarming rate. A few species are still sometimes listed as members of Lebias although that generic 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.

References

  1. Bardakci, F., N. Tatar and T. Hrbek. 2004 - Biologia, Bratislava 59(5): 559—566.
    Genetic relationships between Anatolian species and subspecies of Aphanius Nardo, 1827 (Pisces, Cyprinodontiformes) based on RAPD markers.
  2. 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).
  3. Hrbek, T., F. Küçük, T. Frickey,K. N. Stölting, R. H. Wildekamp and A. Meyer. 2002 - Mol. Phylogenet. Evol. 25(1): 125-137.
    Molecular phylogeny and historical biogeography of the Aphanius (Pisces, Cyprinodontiformes) species complex of central Anatolia, Turkey.
  4. Wildekamp, R.H., F. Küçük, M. Ünlüsayin, and W. V. Neer. 1999 - Turk. J. Zool. 23: 23-44.
    Species and Subspecies of the Genus Aphanius Nardo 1897 (Pisces: Cyprinodontidae) in Turkey.

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