Taxonomy & naming
Rakthamichthys anchi was described in 2026 by Ralf Britz, Amanda Pinion, Wimarithy Marak, Kangjam Velentina and Yumnam Lokeshwor in Zootaxa. It extends a genus erected only in 2020 (by Britz, Dahanukar, Standing, Philip, Kumar and Raghavan) to house a cluster of groundwater-dwelling synbranchid eels formerly assigned to Monopterus, and before that to Amphipnous — among them the type species R. roseni and the Western Ghats species R. digressus, R. mumba and R. indicus. R. rongsaw, from the Khasi Hills, was already documented from northeast India before this description; R. anchi is now the second Rakthamichthys species known from that region, extending the genus's confirmed range from peninsular India's Western Ghats into the Brahmaputra valley of Assam. The source material captured for this article did not include the paper's dedicated etymology section, so the derivation of the specific epithet anchi is not stated here rather than guessed.
Like all Synbranchidae, Rakthamichthys belongs to the order Synbranchiformes, not Anguilliformes — the order of the true eels — so its elongate, limbless body plan is a case of convergent evolution rather than close relationship to genuine eels.
Morphology
No standard length or external morphometric description was captured in the source material available for this article; the formal description sits behind a journal subscription, and the species is diagnosed chiefly by internal, osteological and meristic characters rather than by external appearance. Rakthamichthys anchi lacks lateral-line canal pores on the frontal bone, a character separating it from R. rongsaw (Khasi Hills) and from the Western Ghats trio R. roseni, R. digressus and R. mumba. It also carries more preanal vertebrae than that Western Ghats trio — 90–100, against 76–88 — and a total vertebral count of 159, differing from the 162–169 reported for R. indicus. Against R. roseni, the only congener for which detailed osteological data are available, R. anchi differs by several additional skeletal characters not itemised in the source material available for this article. Genetic distance from the Western Ghats species runs to an uncorrected p-distance of roughly 15–20% in the mitochondrial barcoding gene — a substantial split for congeneric eels. Reduced or absent eyes and reduced pigmentation are the expected pattern for a phreatobitic Rakthamichthys recovered from well water, matching its relatives in the genus, though the description available for this article does not itemise these characters explicitly for R. anchi.
Habitat
Rakthamichthys anchi is known only from wells in a small village in Goalpara District, Assam, northeastern India — true groundwater aquifer habitat rather than any open surface water body. The describing authors note that R. anchi was recovered from wells in the very same village that recently yielded Gitchak nakana, a separately described blind, subterranean cobitid loach, a co-occurrence they say 'highlights the presence of a formerly unknown and highly dynamic subterranean habitat: the groundwater aquifers in alluvial deposits in northeast India.' A broadly similar discovery was made the same year in the alluvial aquifers of Bihar, further south along the Indo-Gangetic Plain, suggesting that India's alluvial groundwater systems as a whole may support a far richer subterranean fish fauna than previously recognised.
Feeding
No dietary information has been documented for this species. Other Synbranchidae, including the groundwater and phreatic relatives within Rakthamichthys and Monopterus, are carnivorous, taking small invertebrates and other prey encountered while foraging through mud, sediment and — in aquifer-dwelling forms — the interstitial spaces of the substrate; this is stated as a general family pattern, not a confirmed observation for R. anchi.
Mating
No mating or courtship behaviour has been documented. The original description is a morphological and osteological account based on museum material collected incidentally from working wells, with no behavioural observations.
Breeding
There is no breeding record for this species in any respect. Synbranchidae generally, including several Rakthamichthys and Monopterus relatives, are known to be protogynous hermaphrodites — maturing first as functional females and later transitioning to male with age or size — but this has not been confirmed for R. anchi specifically and is noted here only as the broader family pattern.
In the aquarium
Rakthamichthys anchi has no aquarium history and no realistic prospect of entering the trade. It is known only from a handful of museum specimens recovered incidentally from wells serving a single Assamese village, and — as a phreatobitic groundwater specialist likely adapted to permanent darkness and stable aquifer conditions — it would not be expected to tolerate ordinary aquarium conditions even if collected. This is a species that should stay in the wild; any commercial collection pressure directed at a single well field would put its entire known population at risk.
Conservation
Rakthamichthys anchi has not been assessed on the IUCN Red List and is recorded here as Not Evaluated. Known only from wells in one village in Goalpara District, Assam, it shares the extreme vulnerability inherent to any species restricted to a single, narrowly defined groundwater system: over-extraction, contamination or disruption of local aquifer recharge could each affect the species' entire known population without any warning visible at the surface. The parallel discovery of a second, unrelated subterranean species — the blind loach Gitchak nakana — from wells in the same village underscores that this aquifer supports a genuinely unusual and apparently fragile assemblage of groundwater-adapted fishes, one that groundwater-quality and extraction management in the region has not yet been designed to protect.