The Vettonian Spined Loach occurs in Portugal and Spain and has a restricted range (area of occupancy (AOO) c. 260 km², extent of occurrence (EOO) c. 11,527), which meet the thresholds for the Endangered category under Criterion B2 (AOO < 500 km²) and Vulnerable B1 (EOO < 20,000 km²) respectively. The extent and quality of habitat are estimated to be declining due to various threats including habitat modification and pollution, and it occurs at nine locations. Therefore, this species is assessed as Vulnerable under Criterion B (B1ab(iii)+2ab(iii)).

This species is endemic to tributaries of the Tagus (es. Tajo; pt. Tejo) River around the border between Portugal and Spain, from the Ponsul River eastwards to the Alagón River. It is also present in the Águeda River, a tributary of the Douro (es. Duero) River system.

This species' current population size and trend have not been quantified, and the number of subpopulations is unknown.

In Spain, there exists clear evidence that its population size has reduced significantly since the late-20^th century, and this pattern is suspected to be ongoing based on field observations and declining habitat quality. For example, it has been extirpated from the lower Águeda River and its tributaries.

The situation in Portugal is less clear, but a series of plausible threats have been identified (see 'Threats').

This species predominantly inhabits the headwaters of minor rivers with low pH and water hardness, and is typically found in stretches with clear water and substrata of boulders, cobbles and gravel, sometimes with patches of submerged vegetation. Discharge and flow can be high in winter and spring, whereas some reaches are largely dewatered during the summer and autumn. The abundance of resident fishes can be significantly reduced during these events, but some individuals survive in remnant pools or short perennial stretches.

It co-occurs and hybridises with the comparatively eurytopic Southern Iberian Spined Loach (Cobitis paludica) across part of its range. For example, it is present in the upper reaches of the Erjas River, while the Southern Iberian Spined Loach occupies slower-moving and more turbid downstream habitats. Hybrid individuals are most abundant in the lower reaches of the eastern Alagón and purportedly the Aravil, Ponsul and lower Erjas rivers, which may be indicative of adaptive divergence.

Like other Cobitis species, it feeds by filtering mouthfuls of fine material through the gills, from which minute organic particles and small benthic organisms are extracted and consumed. It is also a facultative air-breather that makes use of its hindgut as an accessory air-breathing organ.

The annual reproductive period extends from April to June, but little else is known of its life history. Related species tend to spawn among submerged vegetation, where the eggs are retained until they hatch.

This species is threatened by anthropogenic habitat modification, particularly the construction of dams, sills, weirs and other barriers, which interfere with discharge while impairing connectivity and the availability of summer refuge pools. In the Alagón River, water is diverted from some headwater streams to a sewage treatment plant, which further decreases the natural flow rate.

It is also threatened by diffuse and/or point source agricultural, domestic and industrial pollution (e.g., cattle grazing, olive production, untreated domestic wastewater), which has at some locations reduced the extent and quality of habitat due to eutrophication or discharge of toxic substances. Pollution can be particularly impactful during the summer and other periods of low flow, especially in temporal rivers where native fishes are often confined to small refugia (see 'Habitat and Ecology').

Some habitats have also been damaged by increased sedimentation following the removal of riparian vegetation.

A number of non-native aquatic species are established within this species' range, including Eurasian Pikeperch (Sander lucioperca), Pumpkinseed (Lepomis gibbosus), Largemouth Bass (Micropterus salmoides), Eastern Mosquitofish (Gambusia holbrooki), Wels Catfish (Silurus glanis) and Red Swamp Crayfish (Procambarus clarkii), all of which are considered invasive and can exert detrimental pressures on native freshwater fauna through increased competition, depredation or habitat degradation. In Portugal, the Ponsul River is negatively impacted by overgrowth of the non-native floating fern Azolla filiculoides.

It is expected that subpopulations inhabiting intermittent river systems are negatively-impacted by extended periods of dry weather driven by climate change. In 2023, a wildfire in the upper Árrago River is understood to have triggered a significant fish kill after tonnes of ash was washed into the river.

Although it is understood to be a natural phenomenon, introgressive hybridisation with the Southern Iberian Spined Loach is also considered to represent a threat. The two species are believed to gave evolved in allopatry prior to the Quaternary, but later came into contact as a probable result of climatic changes and/or river capture events. At least three non-introgressed Vettonian Spined Loach subpopulations remain extant, and their unique genetic diversity would be compromised if hybridisation occurs.

This species is not used or traded.

The Vettonian Spined Loach is included in Appendix III of the Bern Convention (as Cobitis paludicola) and Annex II of the European Union Habitats Directive (originally as Cobitis taenia).

It is nationally-protected in Portugal, but was assessed as Data Deficient for the Portugese Red Book of Freshwater and Diadromous Fishes (2023). It was assessed as Endangered in the Atlas and Red Book of the Freshwater Fishes of Spain (2002).

A portion of this species' range was included within the framework of the European Union-funded LIFE project 'Cipríber' (LIFE13 NAT/ES/000772), which ran from 2014-2019 in Salamanca Province, Spain. During this project, a number of management actions aimed towards improving fluvial connectivity for fishes were carried out, including the construction of 40 fish passes and partial or complete demolition of 15 dams and other man-made barriers. The results obtained suggested that while barrier removal was successful in terms of restoring habitat connectivity for the target native species, it also permitted some established non-native taxa to enter areas they were previously unable to reach. The implication is that in some degraded fluvial systems the continued presence of man-made barriers might be beneficial for the conservation of native freshwater fishes.

Future conservation efforts should be considered following required research focussed on understanding this species' overall population and habitat trends, plus the extent of the most important threats. Moreover, its distribution and population status in Portugal are poorly understood and in need of further study.

The four identified subpopulations (see 'Population') should be treated as individual conservation units for management purposes. In addition, sites where the Vettonian Spined Loach has not hybridised with the Southern Iberian Spined Loach, i.e., the upper Erjas River and those occupied by the Águeda and Árrago subpopulations, should ideally be prioritised for conservation actions. The status of the Águeda subpopulation is particularly concerning due to its low genetic diversity and declining size, while the upper Árrago River is occupied by multiple non-native fish species and suffered a major environmental disaster during 2023. The Erjas River subpopulation requires careful management, since hybrid individuals might already be present in the lower part of the system.