Physical Characteristics
The roach has an elongated body, slightly compressed laterally, similar to that of the rudd, but with distinct differences. The body is covered with medium-sized scales arranged in regular rows, and the lateral line is slightly curved toward the ventral part. Average dimensions range between 15-25 cm in length and 150-300 grams in weight, but under optimal conditions it can exceed 35 cm and reach 1-2 kg. The coloration is characteristic: the back has a blue-gray or greenish hue, the flanks are shiny silver, and the belly is white. A distinctive feature of the species is the terminal mouth, cut almost horizontally, which differentiates it from other cyprinids. The eyes have a large characteristic red spot in the iris, above and next to the pupil. The fins, except for the dorsal and upper part of the caudal which are paler, have a distinctive red-orange coloration. The caudal fin is deeply forked, giving it agility in movements. The number of scales along the lateral line varies between 39-48, and the dorsal and anal fins have 12-14 rays.
Habitat & Distribution
The roach prefers still or slow-flowing waters with abundant vegetation and muddy or sandy bottoms, being an extremely adaptable species to various environmental conditions. In the Danube Delta, the species is present in permanent and temporary lakes, delta marshes, channels with weak currents, closed arms of the Danube, and confluence areas rich in aquatic vegetation. It tolerates a wide range of temperatures, from 2°C to 22°C, and can survive in waters with medium or even lower oxygen content. The roach is a gregarious species, forming numerous schools especially during the breeding season and in areas with rich food resources. In Romania, it is found throughout the Danube river basin, including in large lowland rivers such as the Mureș, Olt, Argeș, Someș, and Timiș, as well as in natural lakes (Snagov, Căldărușani, Scrovistea) and artificial reservoirs. It is absent from mountain waters and areas with strong currents. During the day, the roach takes shelter in areas with dense vegetation, and in the evening and early morning it comes out to feed in open areas.
Behavior and Feeding
The roach is an omnivorous fish with a varied and opportunistic diet, adapting its food preferences according to season and food availability. The main food consists of zooplankton (rotifers, cladocerans, copepods), aquatic insects and their larvae, small crustaceans, mollusks, worms, and plant matter including algae and aquatic plants. The fry initially feed on unicellular algae and rotifers, gradually moving to zooplankton and later to benthic invertebrates as they grow. The feeding method is characteristic of cyprinids, the fish searching for food both at the water surface and in sediments, where it scrapes the bottom in search of benthic organisms. The roach is a social fish, forming numerous schools that move in groups in search of food. Feeding activity is intense early in the morning and late in the evening, a period when fish come out of sheltered areas with vegetation. In autumn, before winter, food consumption increases significantly for the accumulation of reserves. In winter, activity is drastically reduced and fish take shelter in deeper areas, feeding sporadically.
Life Cycle & Reproduction
The roach reaches sexual maturity relatively early, at the age of 2-3 years, with females becoming mature slightly later than males. Reproduction takes place in spring, between the end of April and May, when the water temperature constantly reaches between 12-14°C. As early as the beginning of April, when the temperature reaches 4-7°C, fish begin to gather in numerous schools in shallow areas with abundant vegetation, preparing for reproduction. The reproduction process is noisy and spectacular, with males often being more numerous than females and actively competing for their attention. The eggs, numbering approximately 100,000-200,000 per female, are sticky and attach to submerged aquatic plants or other surfaces in breeding areas. Fertilization is external, with males releasing milt over freshly laid eggs. Hatching occurs after 5-12 days, depending on water temperature. The fry remain attached to vegetation for a few days, feeding from the yolk sac, then begin to swim freely and seek active food. Mortality in the first weeks of life is high, with fry being prey for numerous species of fish, waterfowl, and predatory invertebrates.
Conservation Status
The roach is classified as "Least Concern" (LC) by IUCN, being one of the most widespread and numerous cyprinid species in Europe. The species does not face major threats at the population level and is stable in almost all its distribution areas. In the Danube Delta, the roach is extremely abundant and plays a vital ecological role as a pivot species in the food chain, being both an important consumer of plankton and invertebrates, as well as an essential food source for predatory species. However, at the local level, populations can be affected by water pollution, eutrophication, hydrological modifications, and overfishing. The species does not benefit from special protection measures in Romania, and fishing is permitted without minimum size restrictions. The roach can be retained at any time of the year outside the general prohibition, which applies to all cyprinid species during the breeding season. Due to its abundance and rapid reproduction capacity, the species is considered a good indicator of the health of aquatic ecosystems. The presence of roach in large numbers usually signals a balanced and productive aquatic ecosystem.
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