Fish Lice (Argulas)

Fish Lice (Argulas)

Argulus or fish lice as they are commonly called are a very major threat to your fish’s health. They can cause significant morbidity and mortality when heavily infesting your fish and they have been known to be the vehicle for other fish diseases. Argulus are a crustacean parasite in the subphylum Crustacea, which groups them together with prawns, shrimp, water fleas and others. The animals that are in the Crustacea group have semi-rigid to rigid chitin exoskeleton. The chitin exoskeleton will molt, or shed, as they get larger. Argulus are in the Branchiura class, which is group of Crustaceans that all have similar features. All of the Branchiura are fish parasites.

Argulus another crustacean parasite, round and up to 1cm wide. They have a sucker to hold on to the Koi with needle-like mouth parts which they stick into the Koi and inject a toxin. This causes intense irritation to the Koi and they scratch and jump and can cause bacterial infection.

Argulus have a direct life cycle using only the fish as hosts. They prey upon freshwater fish and marine fish. Argulus can spend a large amount of time swimming around and mating occurs when the male and female Argulus are swimming. The eggs clusters are dropped on any convenient submerged item. After hatching the Argulus makes several metamorphic changes as it goes towards adulthood. The whole cycle takes between 30-100 days depending on the temperature. After hatching they must find a host within a around 4 days or they will not survive.

If they infect the gills they cause severe damage and often death. Most antiparasite remedies will not kill fish lice, a strong chemical is needed which is not freely on sale. Ask a professional dealer or vet.

See More Parasitic Koi Diseases

Anchor Worm (Lernaea)

Anchor Worm (Lernaea)

Crustacean parasite, Lernaea - Anchor worm is a common parasite on our Koi which is clearly visible to the naked eye and can reach 10 to 12mm. The parasite burrows its head into the Koi's tissue, under a...(click on product image for more details)
Costia

Costia

Costia is a minute Flagellate with 3-4 flagella. It affects both the skin and gills of Koi, and reproduces itself by binary fission. Infestations of this parasite can appear very rapidly indeed, and Koi...(click on product image for more details)
Gill Maggots

Gill Maggots

Gill maggots are the mature females of the parasitic crustacean Ergasilus. Ergasilus (gill maggots) will appear as grayish black and white parasites several millimeters long infesting the gills. Heavy...(click on product image for more details)
Skin and Gill Flukes

Skin and Gill Flukes

Gill and Skin flukes are two of the family of monogenetic trematode genera, all of which are characterised by the large grappling hooks which are used to attach themselves to their victims. Flukes are...(click on product image for more details)
Trichodina

Trichodina

Trichodina is one of the easiest protozoan parasites to detect under the microscope as it is almost perfectly round with hundreds of hooks which resemble cilia found its periphery and it constantly rotates...(click on product image for more details)
White Spot (Ich or Ichthyophthirius)

White Spot (Ich or Ichthyophthirius)

Caused by Ichthyopthirius multifiliis. The white spots on the skin, gills and fins are individual protozoan cells that are under the skin and feed on the body fluids and cells. They then punch out of the...(click on product image for more details)