Which parasite is known as fish lice and commonly found in both freshwater and saltwater?

The identified parasite known as fish lice is Argulus. This is a genus of crustaceans that are ectoparasites, primarily affecting fish by attaching themselves to the skin, fins, and gills. Argulus can be found in both freshwater and saltwater environments, making them a widespread concern for aquaculturists and fishkeepers.

Argulus is characterized by its flattened, oval body and the presence of compound eyes, which distinguishes it from other types of parasites. These parasites feed on the bodily fluids of fish, leading to irritation, inflammation, and secondary infections due to the damage they cause to the fish's skin.

Ichthyophthirius is a protozoan that causes "ich" or white spot disease, which is a different type of infection affecting the skin and gills of fish, primarily in freshwater.

Gyrodactylus is a genus of monogenean parasites that primarily infect fish, but they are not referred to as fish lice. They are typically found on the gills or skin of fish, but their life cycle and morphology are distinct from those of Argulus.

Mycobacterium is a genus of bacteria known to cause chronic infections in fish, but it is not a parasite in the same sense as