The culture of common dentex (Dentex dentex, L. 1758) began at the beginning of the mariculture development in the Mediterranean due to the great interest of the market. It is characterized by fast growth and a small conversion ratio. Survival is extremely low accompanied by a number of health problems. Common dentex is being cultured in floating sea cages which allow contact with wild animals. In such a farming system there is a chance of a possible transition of parasite Microcotyle erithrini (Van Beneden & Hesse, 1863) from wild animals to the cultured fish species. The parasite is common monogen that with the help of skeletal structures inhabit the gills of fish, feeding on the blood of the host, and thereby causes anemia and asphyxia, which ultimately leads to the mortality of individuals themselves. It is present in the population of arbuns (Pagellus erythrinus, L. 1758), bouge (Boops boops, L. 1758) and common dentex (D. dentex). This research followed the prevalence and impact of parasites on common dentex for a period of five months. Sampling was done in September, October, November and December during 2019 and in January 2020 on a total of four cages at one breeding site. Sea temperature was monitored daily. High mortality rate of individuals in September was found to be directly related to the presence of stress and high sea temperatures. During this period, 200 dentex were examined and 3 of them were infected with M. erithrini. Due to the small number of parasites found, it was not possible to determine their impact on survival, hematocrit and fish growth, so further research is needed.