Description and characteristics
The crucian carp (Carassius carassius) is a freshwater cyprinid with a deep, massive body covered with large, golden-green or bronze scales. It resembles the goldfish but has a deeper body and usually a more golden colouring.
Habitat and distribution
It prefers stagnant, marshy, vegetated waters of the Danube Delta — ponds, marshes, canals and shallow lakes. It tolerates conditions with low oxygen very well.
Diet and behaviour
It feeds on benthic invertebrates, larvae, vegetation and detritus. It lives in schools, is active during the day and is a robust, gregarious species.
Reproduction
Spawning occurs in spring at 14–18°C, with females laying eggs on vegetation and bottoms. It is a prolific species with a short life cycle.
Economic and ecological importance
It has local value for consumption and recreational fishing. Ecologically, it contributes to stagnant-water ecosystems where other species are less resilient.
Threats and conservation
Although resilient, it is sensitive to the loss of marshy habitats and competition with introduced species. Protecting ponds and marshes is important.
Fishing and legal minimum size
Crucian carp is caught with a rod in stagnant waters. In the table of minimum legal sizes, the crucian carp (Carassius carassius) has a minimum legal size of 17 cm.
Conclusion
The crucian carp is a robust cyprinid adapted to the stagnant, marshy waters of the Danube Delta.