Male Stickleback in Breeding Condition (image) University of Leicester Caption Male stickleback in breeding condition attending his nest. Heavily infected fish are rarely able to reproduce. Credit University of Leicester Usage Restrictions Use only with credit. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.