Ichthyophthiriasis in the mirror carp Cyprinus carpio (L.) IV. Physiological dysfunction*

Changes in blood ion concentration, oxygen absorption, blood haemoglobin concentration and blood urea‐ammonia nitrogen level were measured in a group of mirror carp, Cyprinus carpio (L.) infected with measured numbers of Ichthyophthirius multifiliis under standardized conditions. The disease was characterized by a drop in serum sodium and magnesium and increase in serum potassium. The ability of infected fish to absorb oxygen was reduced as was their ability to tolerate dissolved oxygen concentrations under 5 ppm. Blood ureaammonia level was elevated during the disease but blood haemoglobin level remained unchanged.