Prosorhynchus spp., Pseudohaliotrema spp., and Paraniza larva formed a mixed parasitic infestation that was isolated from 120 red mullet fish (Mullus surmuletus) from the city of Safaga at the Red Sea governorate. Prosorhynchus spp. digenetic trematodes were found in a clear transparent sac in the buccal cavity; its prevalence was 65%. Pseudohaliotrema spp. Monogenetic trematodes were distributed in the gill fish with a heavy infestation in prevalence (84%). Paraniza larvae on the gills, fins, and tongue were recorded (32%). This mixed parasitic infestation caused suffering from respiratory manifestations with symptoms obvious in infested fish, such as congestion and erosion of gills in addition to excessive mucus secretion. For validation and identification of pathogenic Prosorhynchus spp., cox1gene was used by conventional PCR. The sequence was submitted to the Gene Bank (Accession No. OP103715). In the phylogenetic trees, our cox1 sequence had a close relationship and was clustered into one branch with the members of Family Bucephalidae.