Taxonomy & naming
Eidinemacheilus proudlovei was described in 2016 by Jörg Freyhof, Hemin Abdullah, Mustafa Ararat, Neamat Ibrahim and Daniel Geiger in Zootaxa, on the basis of specimens collected from a subterranean spring in the Little Zab River drainage of Iraqi Kurdistan. It is the second described species in the genus Eidinemacheilus, joining Eidinemacheilus smithi, which had stood alone as the only known troglomorphic (cave-adapted) nemacheilid loach in the Middle East since 1976. The genus sits within Nemacheilidae, the stone and brook loaches — by far the largest loach family, and one the Catalog of Fishes continues to revise as species once lumped under broad genera like Nemacheilus or Noemacheilus are redistributed into narrower, better-supported genera such as this one.
The species epithet honours Graham Proudlove, a researcher noted for his work on subterranean and cave-dwelling fishes. DNA barcoding on the type material showed more than 8% genetic (K2P) distance from every other nemacheilid loach sampled across the Middle East, Europe and western India, supporting its status as a distinct species rather than a population of E. smithi. The original description separates the two Eidinemacheilus species by details of the caudal fin ray count (8+8 or 8+7 branched rays), the absence of an adipose keel, enlarged jaws and a fully developed head lateral-line canal system.
Morphology
Eidinemacheilus proudlovei is a small loach, reaching a maximum recorded standard length of only about 2 in — modest even by the standards of the stone and brook loaches. As a troglomorphic species it shows the classic cave-fish suite: no functional eyes and no body pigmentation, leaving it pale and effectively colourless, the outward signature of generations spent in permanent darkness. Like other nemacheilids it likely carries the small, erectile suborbital spine typical of the family, along with the near-scaleless skin that makes this whole group sensitive to medication — though no aquarium-husbandry data exists to confirm how these traits manifest in life, since the species has never been kept.
The original description leans on fine anatomical detail to separate it from its closest relative, E. smithi: enlarged jaws, a fully developed cephalic lateral-line canal system, and specific caudal-fin ray counts. These are the kind of characters that matter for identifying preserved museum specimens rather than field observation, underlining how little of this fish's biology has been studied outside the original taxonomic work.
Habitat
The species is known only from its type locality: an ephemeral spring near the village of Kanishok in Iraqi Kurdistan, within the Little Zab River drainage — a major tributary system of the Tigris. This is genuinely subterranean, groundwater habitat, not a surface stream; the fish lives in permanent darkness in water emerging from underground aquifers, with no access to sunlight and, presumably, sharply limited food input compared to an open stream.
Beyond the fact of its subterranean, spring-fed setting, essentially nothing has been published on the physical or chemical conditions of the water itself — temperature, flow, pH and mineral content have not been documented in the available sources. This kind of single-locality, cave-associated distribution is common among troglomorphic nemacheilids and leaves the species highly vulnerable to any disturbance of that one spring.
Feeding
No dietary studies have been published for Eidinemacheilus proudlovei. Cave-adapted nemacheilids in general are presumed to be opportunistic micro-predators and scavengers, taking whatever small invertebrates, organic detritus or microbial biofilm washes into their groundwater habitat from the surface — a food supply that is inherently scarce and irregular compared to an open, sunlit stream. Given the extreme habitat specialisation of this fish, its feeding ecology should be considered essentially unknown rather than inferred with confidence.
Mating
Nothing has been published on courtship, spawning behaviour or sexual dimorphism in this species. No aquarium or field observations of reproduction exist. As with feeding, what can be said follows only from what is known of the wider stone and brook loach family: nemacheilids as a group are egg-scatterers with no pair-bonding or nest-building behaviour, but whether that pattern holds for a subterranean, permanently dark-adapted species like this one has not been documented.
Breeding
There is no breeding record for Eidinemacheilus proudlovei, in the aquarium or otherwise — it is not held in the hobby and has, as far as the available sources show, never been bred or observed spawning by researchers. Stone and brook loaches as a family are typically egg-scatterers that release eggs over gravel or among stones in fast-flowing water, with no parental care, and are rarely bred even in captivity by specialists. For this species that general pattern is a reasonable assumption rather than a documented fact; the honest position is that its breeding biology is unknown.
In the aquarium
Eidinemacheilus proudlovei is not an aquarium fish. It is a narrow-range subterranean endemic collected for scientific study from a single spring, and there is no history of it being kept, traded or bred in captivity. Its extreme specialisation to a lightless, groundwater habitat — no eyes, no pigmentation, and presumably a very particular water chemistry and food supply — would make it a poor and unethical candidate for the trade even if it were available, and no husbandry guidance exists because none has ever been attempted.
Conservation
Eidinemacheilus proudlovei has not been evaluated by the IUCN Red List and carries no formal conservation status. That gap is a genuine cause for concern rather than reassurance: the species is known from a single ephemeral spring near Kanishok village in Iraqi Kurdistan, and any groundwater extraction, drilling, pollution or disruption of that one site could threaten its entire known population. Single-locality subterranean endemics like this one are inherently at high risk from habitat disturbance even when — as here — no formal assessment has yet quantified that risk. It is not part of the aquarium trade, so collecting pressure is not a factor; the concern is entirely about the integrity of its one known spring.