Die Schleie, auch der Schley genannt, gehört zu den Karpfenartigen und lebt überwiegend am Grund langsam strömender oder stehender Gewässer. Die robusten Schleyen haben den geringsten Sauerstoffbedarf und bilden in einigen Gewässern wie Dorfteichen, Tonkuhlen, Moorstichen und stark verkrauteten Waldteichen die einzige Fischart.

The tench, also called the Doctor Fish -- or in Germany, Schlei (as well as Herr Doktor Fisch) -- is a member of the carp family which lives mainly on the bottom of slowly flowing or standing waters. The Mighty Schley, together with the crucian carp, tolerates water with the least oxygen concentration of any fish. It is the only species of fish to be found in some waters, such as village ponds, clay waterholes, fen pools and weed-infested forest ponds, where even the nasty carp cannot survive.