chondracanthids

Chondracanthids are a family of parasitic crustaceans belonging to the order Poecilostomatoida. These parasites are obligate ectoparasites, meaning they live on the external surface of their host and cannot survive independently. Chondracanthids primarily infect marine fish. They are characterized by their extreme sexual dimorphism, where the females are much larger and more robust than the males. The females attach themselves firmly to the host fish, often burrowing their cephalic appendages into the host's tissues. Their bodies are typically sac-like or club-shaped.

The life cycle of chondracanthids involves a free-swimming larval stage that infects a new host. Once attached, the female undergoes significant morphological changes, adapting to a sessile parasitic existence. Males are small and often live attached to the female, their sole purpose being reproduction. These parasites can cause damage to their hosts, including inflammation, tissue erosion, and secondary infections, although the severity of the impact can vary depending on the host species and the intensity of the infestation. Their presence is usually confined to specific areas on the host, such as the fins, gill cavities, or body surface.