柯脂鲤 · Hazar Toothcarp

Overview

Endemic to Turkey's Lake Hazar, Kosswigichthys asquamatus is an elongated killifish with almost no body scales. It schools outside the breeding season. Particular dissolved salts appear important for normal egg and fry development, so suitable temperature alone does not establish appropriate water conditions.

Distribution & habitat

The species is confined to Lake Hazar in southeastern Anatolia's eastern Taurus region, not Iran. Historical irrigation drainage greatly lowered the lake. Its restricted range, continuing pollution, and siltation leave the population vulnerable to environmental change.

Lake water is hard, alkaline, and rich in magnesium chloride. Fish use open water more than many related toothcarps, with males establishing breeding sites around algal rocks in warmer months.

Aquarium setup

Fine yarn mops, filamentous algae, and other cover provide refuges and attachment surfaces. Marine salt at about 1–2 g/L is recommended, which can limit ordinary fine-leaved plant growth. Bare bottoms or inert sand and gravel are options; strong current is unnecessary.

Alkaline, mineral-rich conditions are important. Gypsum and Epsom salts have been used to support egg and fry development, but no precise recipe is supplied, so an arbitrary dosage cannot be inferred. Provide several cool winter months rather than constant warmth, which may reduce reproduction and longevity. Outdoor care and some natural sunlight depend on a suitable local climate.

Diet & feeding

Historical feeding advice for the related group includes small live or frozen brine shrimp, water fleas, and bloodworms, with dry foods usually learned. Regular feeding is especially relevant during spring and summer reproduction. A Spirulina-containing preparation can supplement a system lacking filamentous algae.

Behaviour & compatibility

A dedicated breeding group is preferable, ideally with two or three females per male. Males are relatively less aggressive than some relatives, and schooling occurs outside reproduction. Breeding still requires room for separate sites and retreats.

Sexual dimorphism

Males have around eleven to fifteen dark bars and small head spots, becoming much darker when breeding. Females are larger and plainer, with flank blotches and clearer fins.

Breeding

Repeated small spawnings generally occur from April through September. Males court within temporary territories, and eggs attach to algae or other surfaces with fine filaments. Daily checks and transfer of egg-bearing material help reduce losses to predation.

The tiny eggs require careful handling without direct gripping. Match incubation water to the adults in temperature and chemistry. Hatching usually takes twelve to seventeen days. Begin with infusoria-sized foods, then move to newly hatched brine shrimp or microworms after several days of growth.

Notes

Nearly absent scales, an elongated body, and conical teeth characterize the fish. Historical accounts mix genus names and scale descriptions, making reliable provenance more useful than a general scaleless killifish label.