Helminthic Diseases in Fishes

a. Dactylogyrosis disease:

• The monogenic trematode, Dactylogyrus is reported to cause serious infection in fishes. D. exitensis, D. vastator and D. lamellatus are found in carps.
• These are found on the body, fins and gills.
• The parasites start appearing in the ponds during the raining season. But, their prolific multiplication takes place during winter, when the intensity of infection on carp fry may reach as high as 94%.
• The most infected size group is 61-100 mm, irrespective of species.
• Infected fishes rest near the surface of the pond margin, swim very slowly, feel suffocation, more slimy, dropping and folding of fins and pale gills.
• Alternative baths with 1:2,000 acetic acid and 2% sodium chloride are effective.
• 10 ppm of potassium permanganate bath for 1-2 hours and 5 ppm in the pond may give good results.
• Bromex – 50 (0.18 ppm) and Dylox (0.25 ppm) are effective to control the disease.

b. Gyrodactylosis disease:

• Monotreme trematode, Gyrodactylus causes disease in culture ponds.
• This lives on fins and on the body of the fish.
• The symptoms are production of more slime, damage of fins and fading of the body colour.
• The medicines used in control of Dactylogyrosis are also effective to control this disease.

c. Other helminthes disease:

• Diphyllobothrium, Bothriocephallus, Diplostomum, Clinostomum, and spring headed worms (Acanthocephala) cause diseases in fishes.
• Nematodes also cause diseases in fishes of which some of the common nematodes are Phillometra and Camallanus.