Xanthochroic stone moroko Pseudorasbora parva (Temminck & Schlegel, 1846) found during eradication of this invasive alien species in Poland

The freshwater fish stone moroko Pseudorasbora parva is one of the most well-known invasive alien species in Europe. To reduce the significance of the threat posed by the spread of this species, coordinated actions are taken at the EU level. They involve the eradication of this species whenever it is observed in the environment. An example of such an action was the catch of this species in an artificial water reservoir in the Saxon Garden in Warsaw, Poland. During 5 days of catching using nets, traps and gradual emptying of water from the reservoir, a total of 10,196 specimens belonging exclusively to the species P. parva were removed. Among them, seven xanthochroic specimens were found, the first ones described in this species to the authors’ knowledge. The unique colour of these individuals is likely genetically determined.