Vörösvértestén

Vörösvértestén, also known as "red blood cell stone" or *erythroclast* in scientific terminology, is a rare and poorly understood phenomenon observed primarily in certain species of freshwater fish, particularly in the Danube River basin. The term originates from Hungarian, where *vörösvér* means "red blood" and *tészté* refers to a dough-like or gelatinous substance, describing the appearance of the affected tissue.

This condition is characterized by the formation of dense, gelatinous masses within the fish's blood vessels or internal organs, composed primarily of aggregated red blood cells. The exact cause remains unclear, but it is believed to be linked to environmental stressors such as water pollution, temperature fluctuations, or parasitic infections. The affected fish often exhibit symptoms such as lethargy, loss of appetite, and visible abnormalities in their flesh, which may appear discolored or swollen.

Vörösvértestén has been documented in species like the Danube bleak (*Alburnus alburnus*) and other cyprinid fish. While the condition does not typically pose a direct threat to human health, it raises concerns about aquatic ecosystem health and the broader impacts of environmental degradation. Research into the phenomenon remains limited, with most studies focusing on its occurrence in specific regions rather than its underlying mechanisms.

The condition has gained attention in scientific and conservation circles due to its potential as a bioindicator of water quality. Further investigation is needed to fully understand its causes, prevalence, and implications for fish populations and aquatic environments.