Mediterranean killifish
Aphanius fasciatus
A small killifish native to the Mediterranean basin, among the very few European aquarium fish. Males display vertical silver and blue bars on an olive background, while females are more subdued with scattered spots. Extremely adaptable in nature — tolerating salinity from fresh to hypersaline, temperatures from 10 to 32 °C, and oxygen-poor water — yet paradoxically difficult in a general aquarium because it requires seasonal management, hard alkaline water, and containment of male territoriality. Threatened by habitat loss and invasive species: hobbyists play a key role in its conservation.
Wassertemperatur
15 - 28 °C
pH-Wert
7.5 - 8.5
Wassertyp
Süßwasser / Brackwasser
Tankfüllstand
Oberfläche und Mitte
Erwachsenengröße
6 cm
Mindesttankvolumen
>= 60 L
Mindestgruppe
>= 4
GH
12 - 30 dGH
KH
6 - 15 dKH
TDS
240 - 600 ppm
Leitfähigkeit
375 - 938 uS/cm
Artbeschreibung
Geographical Origin and Habitat: Endemic to the Mediterranean Sea basin (Italy, Greece, North Africa). Populates the brackish waters of lagoons, estuaries, salt pans and coastal swamps subject to extreme thermal and salinity excursions.
Taxonomy and Morphology: Mediterranean Killifish (Aphanius fasciatus). Small, stocky and robust cyprinodontiform. A "relict" species adapted to survive in extreme conditions (euryhaline and eurythermal). Small mouth turned upwards to catch mosquitoes.
Social Behavior: Gregarious, lives in large schools that incessantly patrol the surface of the water. Males are exhibitionist and vivaciously territorial towards other males, competing for the favor of the female school.
Coloration and Sexual Dimorphism: High dimorphism. Females are uniform olive-green with faint gray vertical stripes. The breeding male "lights up": dark metallic gray background, jet black dorsal fin and bright silvery-blue zebra stripes (hence "fasciatus").
Pflege, Zucht und Mitbewohner
Aquarium Setup: Specific brackish water tank (minimum 80 cm / 32 inches for a school). Shallow water and wide swimming surface. Sandy bottom with macroscopic algae (Caulerpa) or dwarf mangroves. Tank cover useful against jumps.
Diet and Feeding: Essentially carnivorous micro-predator. Its primary meal in nature is mosquito larvae, which is why it is very useful as a biological controller. In the aquarium it accepts crumbled flakes, daphnia, brine shrimp and bloodworms.
Water Quality: Withstands impressive thermal variations (from 10° to 35°C / 50° to 95°F in nature), although a range of 15-28°C (59-82°F) is ideal in the tank. The addition of marine salt is crucial (salinity 5-25 ppt). In pure fresh water, their immune defenses collapse.
Compatibility and Cohabitation: Due to its needs for brackish and alkaline water, it must be kept in dedicated (monospecific) tanks. They tolerate pairing with wild Mollies or brackish gobies (e.g. Brachygobius).
Aquarium Breeding: Quite simple. During the summer (warm temperatures), males attract females into the thick of the algae (Mop). Females lay viscous eggs adhered to the vegetation every day. Parents prey on their own offspring if malnourished.
Risks and Diseases: Extremely sensitive to Oodinium and fungal infections if forced into fresh water for prolonged periods. A constant salt intake is the only preventive medicine they need.
Geografische Herkunft und Verbreitung
Endemic to the Mediterranean Sea basin (Italy, Greece, North Africa). Populates the brackish waters of lagoons, estuaries, salt pans and coastal swamps subject to extreme thermal and salinity excursions.
Ursprung
Kosmopolitisch oder eingeführtAfrika und MadagaskarEuropa, Mittelmeerraum und Westasien
Fischprofil
- Temperament
- Territorial
- This species exhibits a somewhat spirited temperament, being active and occasionally territorial, particularly among males during spawning periods. Males will establish small territories and display intense coloration and sparring behaviors to ward off rivals. While generally peaceful towards unrelated, non-competitive species, they can be nippy if kept in cramped conditions. Providing sufficient space and hiding spots is key to managing their territorial behavior.
- Diät
- Omnivore
- Aphanius fasciatus is an opportunistic omnivore with a diet that naturally consists of aquatic insects, small crustaceans, algae, and detritus. In captivity, they should be offered a varied diet that includes high-quality flakes or micro-pellets, alongside live or frozen foods such as brine shrimp, daphnia, and bloodworms. Incorporating vegetable matter or spirulina-based foods is beneficial to mimic their natural grazing habits. A diverse diet supports their immune system and overall coloration.
- Lebenserwartung
- 3-7 years
- Erwachsenengröße
- 6 cm
- Geschlechterverhältnis
- Harem
- It is highly recommended to keep Aphanius fasciatus in a harem setting rather than pairs to disperse male aggression. A stocking ratio of one male to three or more females works best to ensure females are not overly harassed. In larger aquariums, multiple males can be kept together, provided there are enough females and plenty of visual barriers to define territories. Keeping them in groups also encourages more natural interactions and displays.
- Fütterungsfrequenz
- Twice daily
- It is best to feed Aphanius fasciatus small portions two to three times a day. Frequent, smaller feedings are more aligned with their natural foraging behavior and prevent food from decaying on the substrate. Only offer as much food as they can consume within a couple of minutes to keep water quality high. Fasting them for one day a week can also help maintain their digestive health.
- Bioload
- Low to Medium
- Due to their small size, the individual biological footprint of Aphanius fasciatus is relatively low. However, because they are typically kept in groups or harems, their collective waste requires efficient biological filtration. Regular water changes and a well-established filter are crucial to maintain clean conditions, as they are highly sensitive to spikes in ammonia, nitrite, and excessive nitrates. Keeping organic waste minimal ensures their health and vibrant coloration.
- Fluss
- Strong
- In their natural habitats, which include lagoons, marshes, and slow-moving coastal waters, they experience very gentle water currents. Consequently, they prefer a weak to moderate water flow in the aquarium. High, turbulent currents should be avoided as they can stress the fish and cause exhaustion. Gentle filtration, such as a sponge filter or a baffled power filter, is ideal for creating their preferred calm water conditions.
- Sprungrisiko
- Yes
- Like most killifish and close relatives, Aphanius fasciatus is an agile swimmer capable of jumping out of the water when startled or chasing tankmates. A tight-fitting lid or cover slide is absolutely essential to prevent accidental escapes. Any small gaps around filter pipes or cords should be securely sealed. Floating plants can also help cover the surface and reduce the fish's urge to jump.
- Reproduktion
- Oviparous
- Reproduction in captivity is moderately difficult but highly rewarding, as they are non-annual egg-scatterers. During the breeding season, which is triggered by warm temperatures and increased lighting, males will display to females and deposit adhesive eggs on fine-leaved plants or spawning mops. The parents do not care for the eggs and may consume them, so it is advisable to remove the spawning medium to a separate rearing tank. The fry hatch in about 10 to 14 days and can be raised on infusoria and freshly hatched brine shrimp.
- Kompatibilität & Tankkameraden
- Community
- Due to their specific water requirements, particularly their tolerance for brackish conditions, they are best kept in a species-specific setup. If kept in a community tank, they should only be housed with peaceful, robust species that share a preference for hard, alkaline, or brackish water, such as certain livebearers. Avoid keeping them with long-finned or slow-moving fish, as their active nature can lead to fin-nipping. Small, delicate tankmates or potential competitors should also be avoided to prevent stress.
- Tankfüllstand
- Top/Middle
- In the aquarium, Aphanius fasciatus mostly occupies the middle and top levels of the water column. They are active swimmers that spend their day exploring open spaces and darting among floating plants or tall vegetation. While they occasionally descend to the bottom to graze on algae or search for benthic food, their primary activity remains in the upper half of the tank. Providing surface cover like duckweed or frogbit helps them feel secure in this zone.
Wissenschaftliche Modelle & Parameter
FishBase
Zugang zu den offiziellen wissenschaftlichen Daten der Art
FishBase v25.04Daten synchronisiert am: 15.06.2026
- Trophäenniveau
- 2,7 ± 0,27 se
- Belastbarkeit
- Hoch (weniger als 15 Monate)
- Phylogenetische Einzigartigkeit (PD50)
- 0.5312
- Bayessche Längen-Gewichts-Beziehung
- a = 0.00977, b = 3.24
- AnfälligkeitGeringe Anfälligkeit (10 / 100)
Bildergalerie
Lizenzierte Bilder, die mit der Art oder, wenn markiert, mit dem nächstgelegenen repräsentativen Taxon verknüpft sind.
Verwandte Arten
Empfehlungen gruppiert nach nahen Verwandten, Auswahl von Begleitern und ähnlicher Betreuung.
