|Habitat and Ecology:
In a wide variety of habitats, mainly in lowland areas. Most abundant in nutrient-rich lakes and large to medium sized rivers and backwaters. Takes advantage of channelization, damming and slight organic pollution. Known also from small lowland streams and from brackish coastal lagoons. In fast-flowing rivers, restricted to stretches where backwaters or shelters allow for overwintering. Spawns among dense submerged vegetation in backwaters or lakes, flooded meadows or in shallow, fast-flowing river habitats on plant or gravel bottom.
Lives up to 13 years. Males reproduce for the first time at 2-3 years, females one year later, usually at about 100 mm SL. Undertakes short spawning migrations, sometimes starting as early as September, usually with a peak at temperatures above 9°C in spring. Spawns in April-May, when temperature rises above 12°C. Usually, a whole population spawns within a period of 5-10 days. Spawns in shoals. Eggs are sticky and hatch in about 12 days. Larvae and juveniles inhabit a wide variety of littoral habitats. Feeds mainly on benthic invertebrates, zooplankton, plant material and detritus. Populations predominantly feeding on detritus are often stunted (stunted populations may also be associated with strong year classes). May shift from littoral to pelagic habitats and between benthic food and zooplankton when abundance of a specific food item is high or in order to avoid predation and/or competition. The decision whether to stay in open water or among littoral vegetation is often described as a trade-off between food uptake and predator avoidance. When growing, there is an energetic need to switch from zooplankton to benthic food (chironomids, molluscs). Individuals able to feed on Dreissena mussels increase their growth rate but do not exploit this food source until they have reached about 120 mm SL (at which size they are able to crush the mussels). In some area (Volga reservoirs), pelagic and benthic roach can be distinguished by life-history traits (spawning time, spawning sites). Overwinters in backwaters or in deep parts of lakes. Frequently produces fertile hybrids with Abramis brama.