This study refers to the ecology of Lamproglena clariae. Specimens were collected from the Vaal Dam and Vaal River Barrage in the Gauteng Province, South Africa, for a two-year period. Data were analysed statistically. There was a positive correlation between the host's physical dimensions and the size of the parasite. Larger fish had larger parasites than smaller ones. Parasites from both sites preferred the fourth gill and the median part of the gill arch for attachment. There was no significant host gender preference by parasites. A similar seasonal pattern was observed in the prevalence, abundance, and mean intensity at both localities. This study shows that some aspects of the ecology of the parasite are influenced by the host to which it attaches. Its attachment-site preference was also determined by the position of the gill on the gill chamber. The parasite abundance and prevalence were neither dependent on the size of the host nor influenced by the water quality.