Racovitza's Rudd was endemic to a single location comprising a small, spring-fed lake, from which it was extirpated in September 2014. Ex situ stocks are currently maintained by institutions in Hungary, Czechia and Austria. Therefore, this species is assessed as Extinct in the Wild (EW).

This species was endemic to a single small lake fed by a geothermal spring in the vicinity of Oradea, Bihor County, northwestern Romania. The lake, known locally as Pețea or Ochiul Mare, is located in the upper reaches of the Peța River, a minor left-bank tributary of the Crișul Repede (hu. Sebes-Körös) River in the upper Tisza River system. The Tisza is itself a major affluent of the Danube River.

This species' wild population became extinct in September 2014, following an extended period of declining habitat quality (see 'Threats'). A number of ex situ subpopulations are currently established (see 'Conservation').

This gregarious, thermophilic species inhabited a small (maximum recorded surface area c. 600 m²), shallow (maximum depth < 2 metres) lake fed by a sublacustrine geothermal spring. Under natural conditions the mean annual water temperature in the lake was 29.1°C, but it became progressively colder after the 1960s as a result of the spring's discharge falling from 500 litres/second to 50 litres/second prior to the turn of the century (see 'Threats'). A number of additional springs and two other small lakes in the vicinity are also connected to the Peța River, but this species has not been recorded in any of them.

The lake was heavily-vegetated and supported two other endemic taxa, comprising the melanopsid gastropod Microcolpia parreyssii, which has been globally extinct since the mid-2010s, and water lily subspecies Nymphaea lotus var. thermalis, small numbers of which survive at several other locations in the Peța River system.

Racovitza's Rudd is omnivorous and feeds on aquatic invertebrates and algae, supplemented by smaller amounts of higher plant material.

The annual reproductive period extends from February to March, and the eggs are deposited among submerged vegetation.

This species' extinction in the wild was caused by continued decline in the extent and quality of habitat over a period of several decades, culminating in the drying of Lake Pețea during September 2014.

The primary driver of these events is understood to have been excessive abstraction of groundwater from the geothermal aquifer which feeds the Peța River. This water is partially utilised to heat local homes and guest houses, but also to supply business establishments associated with the wellness, recreational and therapeutic uses of the thermal waters, which are considered to have special properties due to the minerals they contain. The first dedicated tourist facilities were constructed during the 1970s, and extensive investment in new infrastructure during the 2000s prompted a shift from wellness to recreational tourism.

The natural discharge of the geothermal aquifer began to decline after several artesian wells became operational during the 1980s, which caused some smaller springs to dry out. By the mid-2000s, water was being legally abstracted from 29 individual sites, while an undetermined number of illicit boreholes supplying private residences had also been drilled.

Non-native fish taxa introduced to the Peța River include Topmouth Gudgeon (Pseudorasbora parva), Brown Bullhead (Ameiurus nebulosus) and a number of ornamental species that were presumably released by aquarists. The presence of these is likely to have increased resource competition and predation pressure on the Racovitza's Rudd population.

Moreover, the cooling water temperatures plausibly impacted recruitment by disrupting physiological processes associated with reproduction and altering the structure of planktonic and zoobenthic communities in the lake. Foraging and reproductive success may have been further compromised by agricultural (nutrients, pesticides and sediments) and domestic (garbage and wastewater) pollution from an affluent stream, which led to increased eutrophication, siltation and the development of a thick organic substrate layer due to overgrowth of the invasive plants Ceratopteris thalictroides, Bacopa sp. and Elodea sp..

The population size of Racovitza's Rudd is thus believed to have been somewhat reduced prior to dewatering of the lake, which took place over a period of several years. The sublacustrine source spring first became inactive during December 2011, when a sudden decline in depth and surface area was observed. Flow was briefly reestablished in spring 2012, but by the end of that year the lake had been reduced to a small pond measuring a few metres in diameter which was maintained only by intermittent pumping of water from a nearby borehole. These conditions were exacerbated by a series of consecutive dry summers, and in September 2014 the lake completely dried out. This pattern has been repeated in subsequent years, with active groundwater discharge restricted to a short period each spring. By 2017, the number of operational extraction wells had fallen by more than half, indicating severe depletion of the geothermal aquifer.

This species is not used or traded.

This species is included in Appendix III of the Bern Convention (as Rutilus racovitzai).

Lake Pețea and the surrounding area lie within the boundaries of a protected area created in 1932, which was added to the European Union's Natura 2000 network in 2007 (site ROSCI0098). Racovitza's Rudd is not listed as a target species.

In 2012, fears over deteriorating habitat quality resulted in 60 individuals, comprising 58 females and 2 males, being collected from the wild and transferred to the Țării Crișurilor Museum in Oradea with the aid of financial support from the Mohamed bin Zayed Species Conservation Fund. Some of these individuals were later transferred to the Hungarian University of Agriculture and Life Sciences (MATE, formerly Szent István University) in Budapest, Hungary, where reproduction was artificially induced. Around 5,000 individuals were successfully reared as a result of these efforts, which were split between several institutions in order to establish multiple ex situ subpopulations. As of early 2024, stocks are maintained at the Țării Crișurilor Museum (Oradea, Romania), Răsvan Angheluțăq Museum of Natural Sciences (Galați, Romania), MATE, Schönbrunn Zoo (Vienna, Austria), Plzeň Zoo (Plzeň, Czechia) and Tropicarium (Budapest, Hungary).

The Lake Pețea ecosystem and its endemic fauna and flora were targeted by the 'Conservation and protection of ecosystems endangered by lack of thermal and freshwater in crossborder area' project, which took place from 2018-2021 and was co-funded by the European Union within the Interreg Europe interregional cooperation programme (project code ROHU-29). A series of useful studies and conservation activities were completed through a collaboration between the Oradea Metropolitan Development Association, University of Oradea, Aqua Crisius Angling Association and the HUN-REN Institute for Nuclear Research (Debrecen, Hungary), although none of them resulted in long-term outcomes for Racovitza's Rudd.

The reestablishment of this species in the wild is currently precluded by a lack of stable hydrological conditions at the former Lake Pețea, the restoration of which should be treated as a conservation priority. The development of sustainable water abstraction protocols is likely to represent the most effective initial management strategy. If the lake's water level can be restored, a period of monitoring should ideally be implemented in order to assess its ecological status prior to any direct reintroduction efforts.