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Fisheries > Culture Fisheries > Ornamental Fishes

Disease Management

Aquarium fishes develop diseases due to poor environmental condition. Preventing disease is much more economical than providing expensive treatments following disease outbreak. Following steps can be taken to prevent fish diseases.

  • Provide adequate and non-polluted water
  • Provide sufficient space
  • Provide adequate and balanced feed
  • Prevent high temperature fluctuations
  • Remove dead fish, faecal matter routinely
  • Intermittently clean and disinfect the system
  • Always maintain compatible species
  • Avoid unnecessary handling
  • Control internal and external parasites
  • All new incoming fishes should be quarantined from resident stock
  • Separate the infected fishes
  • Provide adequate nursing for diseased fishes

Common disease of ornamental fishes and their treatments



Causative agent



Pinhead size white spots on the body and fins


Protozoan parasite (Ichthyophthirius)

Increase the temperature and treat with 5% methylene blue (1 drop/litre), treat the fish for 1 week

Contagious, observed during sudden drop of water temperature

White spots smaller than above


Unicellular parasite (mono flagellate)

Copper sulphate 0.1 mg/litre for 10-15 min bath


White clumps with cotton like appearance


Fungi including Saprolegnia

1 tsp salt/2 litres water, 1-2 drops of 5% methylene blue or malachite green 2 mg/litre for 30 min dip or 0.1 mg/litre for permanent bath

Favoured by wounds

Swollen eyes


Bacteria, virus, fungi, sometimes together

1% silver nitrate on poped eyes followed by 1% potassium permanganate

Treatment is difficult

Gradual disintegration of fins


Bacterial disease

Surgical removal of ragged portion by a fine sterilized scissors, paint the cut wounded portion by iodine solution. Repeat the same at 12 & 24 hr

Unusual swimming behavior

Swollen abdomen erected scale


Bacterial disease

No known cure. Antibiotics may be tried.

Contagious, difficult to treat

Opercula sticking out, unusual swimming, tiny flukes on the gills


Parasite fluke, Gyrodactylus

Formaldehyde 5-6 drops/litre water dip treatment for 10 min. Repeat for 3 days

Not easy to detect

Red patch in the body

Argulosis/ Learnaeasis

Argulus/ Learnaea ectoparasite

Physical removal of parasites, 15 min bath in 1-2% potassium permanganate, painting the region with iodine soln. Repeat the same after 12 & 24 hr

Violent rubbing due to irritation

(Source: ICAR, 2006)

Chemicals used in treatment

Iodine: Diluted by addition of an equal amount of water to produce a half-strength solution.
Malachite green: Stock solution prepared from zinc-free grade by adding 500 ml distilled water to 1 g malachite green.
Methylene blue: A stock solution is made by adding 1 g medical grade methylene blue to 100 ml warm distilled water.
Potassium permanganate: A stock solution is made by thoroughly dissolving 1 g crystals in 99 ml warm distilled water.


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