Ctenopharyngodon idella (Cuvier et Valenciennes, 1844)

Iftime, Alexandru & Oţel, Vasile, 2025, An annotated systematical checklist of the Romanian ichthyofauna, Zootaxa 5654 (1), pp. 1-64 : 12

Ctenopharyngodon idella (Cuvier et Valenciennes, 1844)

A non-native species, found in aquaculture (with occasional escapes) and frequently stocked for game and commercial fishing; unassisted reproduction is doubtful, but possible, at least sporadically ( Giurcă 1980; Iftime & Iftime 2021; Năstase & Năvodaru 2023; see also Drăgan et al. 2024, who, however, miss the Danube Delta in the given distribution).

Fam. Tincidae

Tinca tinca (Linnaeus, 1758)

A native, widespread freshwater species, living in stagnant or slow-flowing water, in plain or hill areas, in both intra- and extra-Carpathian drainages, in and along the Danube and its major tributaries, the Danube Delta and littoral lakes/lagoons ( Bănărescu 1964; Oțel 2007; Cocan & MireȘan 2018; Năstase et al. 2022; Nagy et al. 2023; Năstase & Năvodaru 2023). Has undergone a considerable decline, but has recovered to some extent (Oțel 2007).

Fam. Acheilognathidae

Rhodeus amarus (Bloch, 1782)

A native, widespread freshwater species, living in stagnant or slow-flowing water, in plain or hill areas, in both intra- and extra-Carpathian drainages, in and along the Danube and its major tributaries, the Danube Delta and some littoral lakes/lagoons ( Bănărescu 1964 [as a subspecies of R. sericeus (Pallas, 1776) ]; Oțel 2007; Cocan & MireȘan 2018; Năstase et al. 2022; Nagy et al. 2023; Năstase & Năvodaru 2023). Bartáková et al. (2019) notice several distinct, mtDNA-defined lineages, of which two (not described, however, as distinct species and apparently intergrading as shown by nuclear DNA data) occur in Romania.

Fam. Gobionidae

Gobio gobio (Linnaeus, 1758) (s. l.?)

A native, widespread freshwater species, found in rivers and sometimes in adjacent stagnant waterbodies, from the plain to the low montane level, in intra- and extra-Carpathian waters ( Bănărescu 1964 [as G. gobio obtusirostris ]; Bănărescu 1999a [as G. gobio gobio ]; Cocan & MireȘan 2018; Nagy et al. 2023). Gobio gobio sensu Bănărescu 1999a was split into several (putative) species (see Kottelat & Freyhof 2007 for their distribution). Of these, the following live in Romania: G. gobio s. str., probably widespread in the extra-Carpathian area, though limited molecular sampling was available ( Bulat 2017; Tákacs et al. 2021); a widespread intra-Carpathian form (“ Gobio sp. 1 ” in Tákacs et al. 2021; “ Gobio gobio sensu lato ” in Nagy et al. 2023) which is distinct in a mtDNA-informed molecular analysis and may pertain to G. gobio s. str. or be a distinct putative species (for which muresius Jászfalusi, 1951 may be available) ( Tákacs et al. 2021); G. carpathicus Vladykov, 1925 , formerly considered to be more widespread in the Carpathian catchment area but limited in Romania (if present at all) to the the Tisza drainage in the MaramureȘ area ( Cocan & MireȘan 2018; Tákacs et al. 2021; Polyák et al. 2022; Nagy et al. 2023 [giving the Tisza/ MaramureȘ records under “ Gobio gobio sensu lato ”]); and G. obtusirostris Valenciennes, 1842 , from (at least) the CaraȘ, Nera and Cerna drainages in the Banat area ( Cocan & MireȘan 2018; Tákacs et al. 2021; Nagy et al. 2023). However, further investigation has shown that the above-mentioned putative Gobio species do hybridize in extensive areas ( Zangl et al. 2020). Treating them (or part of them) together as a “continuum”, “ Gobio gobio sensu lato ” (cf. Tákacs et al. 2018; Nagy et al. 2023), likely corresponding to a single biological species, is probably justified as their genetic distance is small, their diagnosis difficult ( Tákacs et al. 2022), their mitochondrial and nuclear lineages are quite discrepant ( Zangl et al. 2020) and their reproductive isolation is not explored.