Sunbleak

Leucaspius delineatus

The sunbleak (Leucaspius delineatus) is a small cyprinid fish found in freshwater habitats across Europe. Adults reach 6-9 cm in length and display a slender, laterally compressed silvery body with a distinctive bright blue-silver lateral stripe that gives the species a reflective, sun-catching appearance. They form large schools in still and slow-moving waters including ponds, lakes, ditches, and flooded quarries at depths of 0-5 meters. They feed on small invertebrates, insect larvae, and algae near the water surface. Males develop small tubercles on the head during breeding season and guard egg ribbons laid on aquatic plants. Their schooling behavior creates shimmering displays in sunlit freshwater environments. While small, they add life and motion to freshwater dive sites across Europe, and their reflective scales create attractive light effects in underwater photography. They are a common sight in popular freshwater diving locations throughout central and northern Europe.