Esmaeilius isfahanensis (Hrbek, Keivany & Coad, 2006)

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 738-739

Esmaeilius isfahanensis

Common name. Esfahan killifish.

Diagnosis. Distinguished from other species of Esmaeilius by: ● male with black dorsal, pelvic and anal margins / ● female mottled with many large blotches or narrow bars on flank, usually fused into a midlateral, wide, dark-brown band / ○ 25–29 total scales along lateral series / ○ female with a distinctive black spot at caudal base. Size up to 45 mm SL.

Distribution . Iran: Lower Zayandeh drainage (e.g., Hasan Abad, Malvajerd qanats).

Habitat. Springs and spring-fed streams.

Biology. Live up to 3 years, mature in a few months at about 25 mm SL, usually late in year of birth. Males establish territories along banks, usually in dense vegetation but also between rocks, which they defend against rival males. Spawns April–July. Females spawn with one or more males, usually in algae or other vegetation near surface or in gravel beds. Few eggs are laid in the substrate during a spawning event. Individual females may produce several clutches in one day. Feeds on algae, detritus, and small invertebrates.

Conservation status. CR; appears to be declining within its very small range. May have disappeared from Varzaneh.

Remarks. Esmaeilius sophiae inhabits Gavkhoni marshes in very lower Zayandeh drainage. The black spot at the caudal base in the female is much more pronounced in small individuals and fades in large adults of more than 25 mm SL.

Further reading. Hrbek et al. 2006 (description); Keivany 2013 (biology); Esmaeili et al. 2020b (molecular data and distribution); Freyhof & Yoğurtçuoğlu 2020 (genericposition).

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Esmaeilius isfahanensis

Distribution