The Channel Minnow (Phoxinus phoxinus), formerly Common or Eurasian Minnow, was for a considerable period of time treated as the only European member of the genus Phoxinus. However, at least 23 distinct mitochondrial lineages and 14 valid species have been identified in the region since the mid-2000s. This diversity is likely to increase further, as comprehensive information for all major European river systems has not yet been compiled. Moreover, additional sampling plus morphological analyses are required to corroborate some putative species divisions which are currently supported only by inconclusive nuclear data (Denys et al. 2020, Palandačić et al. 2017, 2020, 2022, Bogutskaya et al. 2023).

Taxonomic determination has been further hampered by natural phenotypic variability within the different lineages, plus their disparate geographic distributions which do not generally reflect patterns observed in related European fish genera. Furthermore, anthropogenic translocations linked to recreational fisheries have in some cases led to uncertainty regarding native range boundaries and driven introgressive hybridisation between congeners (Museth et al. 2007, Knebelsberger et al. 2015, Miró and Ventura 2015, Ramler et al. 2017, Vucić et al. 2018, Corral-Lou et al. 2019, Palandačić et al. 2020, 2022, De Santis et al. 2021).

As a result of the increasing species diversity, much of the published literature referring to Phoxinus phoxinus in fact pertains to other taxa and should therefore be reviewed with due care.

Global and European regional assessment: Least Concern (LC)
EU 27 regional assessment: Least Concern (LC)

Although this species' population trend may be decreasing due to habitat degradation, there is no evidence that the rate of decline approaches the minimum threshold for Vulnerable under Criterion A (≥ 30% over the longer of 10 years or three generations). It does not approach the range thresholds for Vulnerable under Criterion B (extent of occurrence (EOO) < 20,000 km², area of occupancy (AOO) < 2,000 km²) or D2. The population size far exceeds 10,000 mature individuals, hence it does not approach the thresholds for Criteria C or D. There exists no quantitative analysis which would permit application of Criterion E.

Therefore, the Italian Minnow does not currently meet the thresholds for any Red List criteria, and it is assessed as Least Concern both globally and for the EU 27 member states.

This species is predominantly native to rivers draining southern slopes of the Alps and northern parts of the Dinaric Karst region in central and southern Europe.

In the Adriatic Sea basin, its range extends eastward from the Po River in Italy to the Zrmanja River in Croatia, including Istria and the island of Krk. Isolated subpopulations inhabit the Esino and Potenza rivers in central Italy, both of which were connected to the Po during the last glacial maximum.

It is also present in the Danube River system, where most confirmed records pertain to tributaries of the upper Drava River downstream to the Mur River, and the upper Sava River downstream to the Una River. However, the precise limits of its range in the Danube catchment are unclear, and additional isolated subpopulations inhabit the Enns River, Austria, and the Drina, Kolubara and Svrljiški Timok rivers, Serbia.

This somewhat patchy distribution has been attributed to a complex evolutionary history, which in the Western Balkans may have been shaped by karstification processes and repeated dispersal through subterranean karstic conduits. Anthropogenic translocation may have also played a minor role.

Introduced subpopulations are established in a number of high-altitude Alpine lakes in the upper Po catchment, Italy, and Triglav National Park, Slovenia.

This species' population size is unknown, but significantly exceeds the minimum threshold for Red List criteria (< 10,000 mature individuals). The current population trend has not been quantified, and the number of subpopulations is unclear.

Field observations indicate that it remains abundant where favourable habitat conditions exist, although declines in abundance have been documented throughout its range since at least the mid-20^th century (see 'Threats').

A total of six distinct genetic sub-lineages have been identified to date, most of which are restricted to the Western Balkans region.

This small-bodied, gregarious species occurs at a range of altitudes, but is most frequently-encountered in upland rivers, streams and oligotrophic lakes. Lowland subpopulations are often associated with freshwater springs.

It is somewhat eurytopic, but demonstrates a preference for relatively lake shallow shorelines or fluvial pools and glides with well-oxygenated, clear water and slow to moderate water movement. At some locations, it may move to deeper areas during periods of cold weather. In the Western Balkans, there is significant evidence indicating that many individuals disperse through subterranean water bodies which they access via estavelles and ponors (see 'Population').

It mostly feeds on aquatic invertebrates, supplemented by smaller quantities of organic detritus and plant material.

The maximum recorded lifespan is 6 years, and adult individuals reach sexual maturity at age 1-2+. The annual reproductive period extends from April to June, but may commence several weeks later and continue until July or August at higher altitudes. This species is a fractional, polygamous spawner, and older individuals tend to spawn earlier in the season. Spawning behaviour is characterised by mature adults migrating short distances to specific sites, usually comprising beds of aquatic vegetation or well-washed gravel. Reproductive males develop a conspicuous epigamic colour pattern, and often aggregate in the vicinity of spawning sites prior to the arrival of females. Epidermal breeding tubercles appear on the head in both sexes, but are more prominent in males.

Construction of dams, sills, weirs and other barriers throughout this species' range has altered natural flow and sedimentation regimes, fragmented subpopulations and plausibly reduced the extent of suitable habitat for all life stages. Hydroelectric schemes have created unnatural discharge and water temperature regimes (hydropeaking and thermopeaking), which bring about artificial dewatering of downstream river stretches and the loss of stable nursery habitat for juveniles. Furthermore, the combined effect of hydropeaking, dam flushing operations, changes in land use, and the removal of riparian vegetation has increased the accumulation of fine sediments at some spawning sites, plausibly impairing the hatching and survival rates of eggs and larvae.

Habitat quality has been further diminished by the industrial extraction of gravel and other sediments for urban development, plus flood mitigation or water abstraction schemes such as bank stabilisation and channelisation.

This species is plausibly impacted by diffuse and point-source agricultural, domestic or industrial pollution at some locations. In the future, some effects of climate change such as increased water temperature or longer periods of low discharge during summer could exacerbate water quality issues, e.g., eutrophication.

Some subpopulations may be threatened by introgressive hybridisation with introduced congeners, e.g., Channel Minnow (P. phoxinus) in Austria, or from predation by non-native fish species such as Rainbow Trout (Oncorhynchus mykiss). At some locations restocking with hatchery-reared Brown Trout (Salmo trutta) may represent a threat due to the risk of over-predation or the transmission of non-native diseases or parasites.

This species is sometimes utilised as live bait by recreational anglers or as feed in salmonid production facilities, but is not otherwise used or traded.

This species is present within the boundaries of various protected areas, including several national parks. In the EU 27 member states, some of these are included in the Natura 2000 network.

Some subpopulations may have benefitted from improvements in habitat and water quality associated with implementation of the European Union Water Framework Directive 2000/60/EC, such as efforts to restore fluvial connectivity through barrier removal or the creation of fishways.

A deeper understanding of its native distribution in addition to its population trend and life history, e.g., the identification of key spawning sites, would likely prove useful to facilitate effective management. Given the nature of its range, such efforts may be best coordinated at separate local or national scales.

In the Western Balkans region, some unique mitochondrial sub-lineages are understood to have restricted ranges and are potentially more susceptible to threatening processes. In the event that direct conservation actions are deemed necessary, care should be taken to avoid hybridisation in order to preserve their inherent diversity.