Perch (German: Flussbarsch, Kretzer, Barschling, Swiss German: Egli, Lat.: Perca fluviatilis) Bream (German: Brachse, Brasse, Lat.: Abramis brama) Northern pike (German: Hecht (Lat.: Esox lucius) Zander (Lat.: Sander lucioperca) Burbot (German: Quappe, Trüsche, Lat.: Lota lota) Eel (German: Aal, Lat.: Anguilla anguilla) Bullhead (German: Groppe, Lat.: Cottus gobio) Tench (German: Schleie, Lat.: Tinca tinca) Wels catfish (German: Wels, Lat.: Silurus glanis) Lake trout (German: Seeforelle, Lat.: Salmo trutta lacustris) The Bodenseefelchen (Coregonus wartmanni), which was named after Lake Constance due to the great numbers found there, is often prepared whole or as a fillet, in the style of the miller's wife (nach Müllerin Art), in local fish restaurants in a similar way to other trout It is also often served smoked. Two endemic species are known to have existed only in Lake Constance, the Bodensee-Kilch (Coregonus gutturosus) and deepwater char (Salvelinus profundus). The former is now assumed to be extinct, while the latter was feared extinct for decades until its rediscovery in the 2010s. Introduced species For many years non-native species have settled in the Lake Constance ecosystem and, in some cases, endangered or threatened native flora and fauna. At Lake Constance, non-native species have been increasing annually. Several have been transported from other waterbodies as 'blind passengers' on the outside of boats, life jackets, anchor chains or ropes or diving gear. Others have immigrated from the Black Sea or the Danube since the opening of the Main-Danube Canal. Others have been deliberately introduced. Well-known non-native species Even the rainbow trout (Oncorhynchus mykiss) is not a native fish. It was introduced into Lake Constance around 1880 for economic reasons to enhance the local fauna. Among the foreign species of animal in Lake Constance are the zebra mussel (Dreissena polymorpha) which, since the 18th century, has spread from the Black Sea region across most of Europe and was carried into Lake Constance between 1960 and 1965. After a huge increase in numbers during the 1980s in the Rhine and large lakes, this species is now in retreat today. The zebra mussel causes problems because, among other things, it blocks water extraction pipes. In addition, the species can be a disaster for domestic shellfish, because it competes for their food. Today, according to the Institute for Lake Research (Institut für Seenforschung, ISF), the zebra mussel is also an important food for overwintering waterfowl. In fact, the number of overwinterers has more than