Home / Fishes / Killifish and livebearers / Scaleless killifish
No federal permit to keepScaleless killifish
Kosswigichthys asquamatus
Fishes › Killifish and livebearers (Cyprinodontiformes) › Aphaniidae (Aphanius killifish)
The scaleless killifish or Hazar toothcarp (Kosswigichthys asquamatus) is a species of freshwater fish in the family Aphaniidae.
Care at a glance
Species-specific aquarium care
- Tank: At least 24 in long and 12 in front to back for one adult (adults commonly reach about 1.6 in / 4 cm).
- Water: Freshwater.
- Temperature: 50–77°F (range recorded for this species).
- Layout: Uses both the bottom and open water: give open swimming space plus cover near the substrate.
Calculated from this species' own FishBase record: tank size from its typical adult length and swimming zone, water values from its recorded ranges. The group guide below fills in general care.
Care guide
Species care notes
- Tank: a base of at least 47 × 12 in (roughly 29 US gallons); space needed is rated “large tank”.
- Water: 54–82 °F, 15–35 dGH.
- Behaviour: a shoaling fish best kept in a group of six or more; not a community fish.
- Difficulty: Moderate (Seriously Fish rating).
Short excerpts from the species profile:
- Setup: “Even for long-term maintenance a simple set-up will suffice although certain aspects of water chemistry appear to be mandatory (see 'water conditions').”
- Diet: “Aphanius species are essentially micropredators feeding on small aquatic crustaceans, worms, insect larvae and other zooplankton although algae and other plant material is also taken at times.”
- Tankmates: “Given its particular water requirements and precarious conservation status we strongly recommend maintaining it alone, the emphasis being on captive reproduction.”
- Breeding: “Captive reproduction is not difficult if the tank or container is properly arranged and maintained (see 'tank set-up').”
From the Seriously Fish profile for this species, which has the full habitat, maintenance, diet, behaviour and breeding write-up 167
Aphanius killifish
Applies to most species in this group. Habitat: These toothcarps occupy vegetated Mediterranean coastal lagoons and inland Anatolian springs, streams and lake margins with locality-dependent salinity (fasciatus, anatoliae). Individual species can differ, so compare with the species numbers above and the linked sources.
Housing & setup
- For fasciatus/anatoliae groups use a footprint of at least 120 × 30 cm; fasciatus pairs/trios can use 60 × 30 cm (fasciatus, anatoliae).
- Fill substantial space with spawning mops or fine-leaved plants to break male sightlines (fasciatus, anatoliae).
- Provide hard alkaline water: fasciatus pH 7.5–9.0, anatoliae 7.0–8.5; both 10–30 dGH (fasciatus, anatoliae).
- Set salinity from collection locality, rather than treating every population as freshwater (fasciatus, anatoliae).
- Use gentle filtration for anatoliae and preserve a seasonal cool winter period (anatoliae).
Diet
- Live or frozen Artemia and Daphnia (fasciatus, anatoliae).
- Bloodworms (fasciatus, anatoliae).
- Spirulina-containing dried food and filamentous algae (fasciatus, anatoliae).
Social life
- Maintain species/locality breeding groups, with two or three females per male for anatoliae and refuges from dominant males (anatoliae).
Health watch
- Ammonia toxicity from inadequate biofiltration (fish_health).
- Parasitic skin and gill infections (fish_health).
- Nutritional deficiencies from unsuitable diets (fish_health).
Understanding the animal
About this animal
About this animal
It is the only species in its genus, and is endemic to Lake Hazar in Turkey. It is a pelagic species that comes to shore in spring–early summer to spawn.
Quoted from the Wikipedia article “Scaleless killifish” (CC BY-SA 4.0) 174
In the wild
In the wild
From this species’ own FishBase record (habitat, bottom type, water and breeding data), not its family. Good care copies these conditions.1
| Where it lives | Lives in freshwater. Uses both the bottom and open water. Not a seasonal killifish. Is very difficult to maintain in the aquarium. |
| Water it lives in | Freshwater, 50–77 °F (10–25 °C). |
| Climate | Temperate climate. |
| Behavior to plan for | Breeding: open water/substratum egg scatterers. |
What this means for care
- Keep water within its wild range, 50–77 °F.
From the sources
From the sources
Quoted from the matching sections of reputable sources for this exact species. Specialist databases are used first; Wikipedia (community-edited, CC BY-SA 4.0) only fills gaps. Other sources are short credited quotes.
| Overview | The scaleless killifish or Hazar toothcarp (Kosswigichthys asquamatus) is a species of freshwater fish in the family Aphaniidae. It is the only species in its genus, and is endemic to Lake Hazar in Turkey. It is a pelagic species that comes to shore in spring–early summer to spawn. It is threatened by the falling water levels of Lake Hazar due to water abstraction and reduced rainfall due to climate change. — Wikipedia (community-edited) |
| Where it lives | Home ranges Population dynamics Growth parameters Max. ages / sizes Length-weight rel. Length-frequencies Mass conversion Recruitment Abundance Life cycle Reproduction Maturity Maturity/Gills rel. — FishBase |
| Biology | Not a seasonal killifish. Is very difficult to maintain in the aquarium. — FishBase |
Data and studies
The numbers
The numbers
Each bar is what one source reports. Where several sources weigh in, the dashed gold band marks their average.
Adult length
Maximum recorded length. Measured as total length. Fish in home aquariums often stay smaller than wild records.
Water temperature
Range the species tolerates in nature; aim for the middle.
Water hardness
Minimum tank footprint
Seriously Fish recommends a tank base of at least 47 × 12 in (about 29 US gallons).
Sources for this sheet
- FishBase (Froese & Pauly, eds.), version 24.07 Peer-reviewed researchThe global scientific database on fishes, maintained by a consortium of research institutions; every value is referenced.
- Seriously Fish species profiles Experienced keeper or breederLong-running aquarium reference written and peer-checked by experienced fishkeepers and ichthyologists; each profile covers habitat, tank size, water, diet, behaviour and breeding.
- Seriously Fish: Aphanius fasciatus Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Seriously Fish: Aphanius anatoliae Experienced keeper or breederAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Disorders and Diseases of Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Merck Veterinary Manual: Management of Aquarium Fish Zoo, university or veterinaryAdded in the 2026 source-checked care-guide review.
- Wikipedia (species article) Community referenceFree encyclopedia; useful overviews with their own citations. Intro text is quoted under CC BY-SA 4.0.
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