Ballerus ballerus also known as zope or blue bream, is a fish native to Eurasia. Cyprinus ballerus feeds mostly on larger zooplankton. In Sweden it is seen in lake Vänern, Hjälmaren, Mälaren and adjoining waters, plus Helgeån waterbody. It can reach sizes for up to about 45 cm, and 0.8 kg.

The Python-based application server Zope is named after the species.^{[citation needed]}

References

• "Ballerus ballerus". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=639435. Retrieved 24 January 2006.
• Froese, Rainer, and Daniel Pauly, eds. (2012). "Ballerus ballerus" in FishBase. January 2012 version.