Calydiscoides euzeti Justine, 2007 is a species of monogenean of the family Diplectanidae Monticelli, 1903. As all members of the family Diplectanidae, it has a single posterior testis and a single ovary that wraps the lateral caecum of the intestine. As all members of the genus Calydiscoides, it is characterized by the presence of lamellodiscs, which are specialized attachment organs made up of concentric lamellae, on the posterior part of its body. The species is distinguished from other species of the genus Calydiscoides by the shape and size of its male copulatory organ, which is elongate in shape with an anterior curved whip, and 70–83 μm in length.