See text Philometra is a genus of nematodes, which are parasites of marine and freshwater fishes.

They parasitize the body cavities, tissues and ovaries of both marine and freshwater fishes.

When still in the larval stages, these worms move to the body cavities or subcutaneous tissues in the host.

This migration can cause damage to skeletal joints, result in internal bleeding, and inflame visceral organs.

When the worms are in the adult or juvenile stage, these nodules may be visible between the rays of the fins or may cause the scales to raise up.