Aphaniops ginaonis (Holly, 1929)

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 723-724

Aphaniops ginaonis

Common name. Genow killifish.

Diagnosis. Distinguished from other species of Aphaniops in West Asia by: ● 5 branched dorsal rays, ½ ray absent / ○ male with 13–19 brown bars on flank / ○ male with 2–3 crescent-shaped black bars on caudal / ○ female with a midlateral row of vertically elongated black, grey or dark-brown blotches or narrow bars / ○ male without black dorsal margin, anal yellow anteriorly, with 3–8 narrow black or brown bands on posterior part of fin / ○ anal and dorsal not reaching to caudal base / ○ body covered by overlapping scales / ○ caudal truncate or slightly rounded. Size up to 40 mm SL.

Distribution. Iran: Genow hot sulfuric spring.

Habitat. A very small hot sulfur spring with 37–40°C water temperatures, bottom of stones and pebbles covered with cyanobacteria.

Biology. Lives up to 6 (female) or 5 (male) years. Matures at 2 years. Spawns probably all year round. Feeds on algae and insect larvae.

Conservation status. CR; declined sharply after the construction of bathing facilities in the spring of the early 21st century. Since then, population has stabilised at a very low level.

Remarks. This species occurs adjacent to the range of A. teimorii that inhabits the outflow of Genow spring below a small waterfall. Both species are well differentiated morphologically, but morphological differences may result from recent adaptations to the extreme conditions of the habitat.

Further reading. Reichenbacher et al. 2009 (habitat, otolith morphology); Golmoradizadeh et al. 2012 (life history).

Only a small part of Genow spring in Iran is inhabited by endemic Aphaniops ginaonis .

Aphaniops kruppi ; Wadi Bani Khalid, Oman ; female, 45 mm SL. Aphaniops kruppi ; Wadi Bani Khalid, Oman ; male, 34 mm SL.