How do monogenean flatworms attach to fish gills?

Monogenean flatworms are ectoparasites that primarily attach to the gills of fish using a specialized posterior attachment organ known as a haptor.12

This complex organ typically features a combination of suckers and strong hooks, which allow the parasite to anchor itself securely to the host's gill tissue. In their larval stage, known as an oncomiracidium, these flatworms are free-swimming and possess numerous posterior hooks that facilitate their initial attachment to a host. Once attached, many monogeneans exhibit highly specific preferences for particular gill arches on the fish.213