Author: (Bloch, 1782)
FBname: European bitterling
Comments: Occurs most abundantly in still or slow-flowing water with dense aquatic vegetation and sand-silt bottom as lowland ponds, canals, slow-flowing rivers, backwaters and oxbows, where mussels are present (Ref. 59043).  Found among plants over sand and muddy bottoms in shallow waters.  Remarkable for its habit of deposing its eggs in the cavity of bivalves (<i>Unio</i>).  Feeds mainly on plants and to a lesser degree on worms, crustaceans, and insect larvae.  Formerly used for pregnancy tests:  females injected with urine from pregnant women protruded their ovipositors (Ref. 6258).  Live span is exceptionally up to 5 years but most individuals do not survive the year of their first reproduction and population sizes fluctuate  greatly over the years (Ref. 59043).