Coexistence of five Dactylogyrus spp. on a single gill arch. Dactylogyrus sp. 1 and Dactylogyrus sp. 2 (in red) exhibit the same anchor morphology (the sclerotized parts of the haptor) and similar microhabitat positions (the dorsal segment (D) and central area of a gill arch (c), but differ in the shape and size of their copulatory organ. Dactylogyrus sp. 3 and Dactylogyrus sp. 4 (in blue) exhibit the same anchor morphology and similar microhabitat positions (the medial segment (M) and central area of a gill arch (c), but differ in the shape and size of their copulatory organ. Dactylogyrus sp. 5 (in green) has a different anchor morphology when compared to Dactylogyrus sp. 1–sp. 4, and is positioned in the ventral segment (V) and proximal area (p) of a gill arch.