Disease Caused By Protozoan In Fish And Its Prevention

Sajid Maqsood*, Prabjeet Singh, Munir Hassan Samoon, Gohar Bilal Wani and Ubair Nisar

Faculty of Fisheries, Sher-e-Kashmir University of Agricultural Science and Technology-Kashmir, India.

*Corresponding author E-mail : simplysajid@gmail.com

1. Protozoan Diseases found in Fish

1. Ichthyophthirius multifilis.

2. Trichodinia sp.

3. Ichthyobodo sp or Costia sp.

4. Chilodonella sp.

1. Disease caused by the infection of Ichthyophthirius multifilis.

• Known as Ich, Ick, or white spot disease

• The most common disease in home aquarium.

• White spot disease is caused by a protozoa called Ichthyophthirius multifiliis.

• There are three phases to the life cycle of this protozoa.

• It is important to know its life cycle because white spot (Ich) is susceptible to treatment at only one stage of the life cycle.

Adult phase

• It is embedded in the skin or gills of the fish, causing irritation (with the fish showing signs of irritation) and the appearance of small white nodules.

• As the parasite grows it feeds on red blood cells and skin cells.

• After a few days it bores itself out of the fish and falls to the bottom of the aquarium.

Free swimming phase

• If a host is not found within 2 to 3 days, the parasite dies.

• Once a host is found the whole cycle begins anew.

• These three phases take about 4 weeks at 70° F but only 5 days at 80° F.

• For this reason it is recommended that the aquarium water be raised to about 80° for the duration of the treatment..

• If the fish can stand it, raise the temperature even higher up to 85°.

Cyst phase

• After falling to the bottom, the adult parasite forms into a cyst with rapid cell divisions occurring

• After the cyst phase, about 1000 free swimming young comes out and looking for a host.

SYMPTOMS

• Salt-like specks on the body/fins.

• Excessive slime.

• Problems breathing (ich invades the gills),

• Clamped fins,

• Loss of appetite.

• Abnormal behavior such as unusual swimming patterns, refusing all food etc.

TREATMENT

• The free swimming phase is the best time to treat with chemicals.

• Raising the aquarium temperature to 80° F will greatly shorten the time for the free swimming phase to occur.

• The drug of choice is quinine hydrochloride at 30 mg per liter.

• Quinine sulphate can be used if the hydrochloride is not available.

• Some aquarists like to use malachite green, but it tends to stain the plastic and silicone in the aquarium. Most commercial remedies contain malachite green and/or copper, which are both effective.
  

1. Disease caused by the infection of Trichodinia sp.

• Circular in shape, with a band of cilia around the circumference.

• Size 40 - 60 microns in diameter, & have a rotating movement.

• They have a disc that has many teeth, which they use to "hook" themselves onto a host.

• The parasites most frequently attack the gills of the infected fish, which causes in heavy infestations, great difficulty in breathing, so that the they come to the surface in a desperate attempt to get sufficient oxygen.

SYMPTOMS

• Behaviour: Lethargy, and scratching against any suitable object

• Breathing at the surface, or just stationary "hanging" at the surface

• Fins: Fins often become clamped or folded.

• Body: The body will manifest darker colours than normal.

• Gills: Gill examination will show large numbers of the organisms , & an excess of mucus.

• Skin (smear): A pale bluish slime is often noticed which covers the skin, this is typically blotchy in nature.

TREATMENT

• Malachite green: 0.2-0.25 ppm .but it is badly tolerated by many of the Tetras, & especially so, by scaleless fish such as Elephant noses & Clown loaches.

• Salt baths: In a 1% solution for about 30 minutes, this repeated for a couple of days.

• Formalin (37%-40%): 250 ppm for about an hour, or 100 ppm for 3 hours. Long term baths 15-20 ppm.

• Acriflavin: Use at 50 ppm as a bath for about 2-4 days.

• Methylene blue: 100 ppm as a bath 2-4 days

1. Disease caused by the infection of Ichthyobodo sp or Costia sp.

• Costia is a minute flagellate with 3-4 flagella.

• It affects both the skin and gills of fish.

• Fish suffering infestations exhibit the classic symptoms of lethargy, clamped fins, rubbing and flashing and the skin can take on a grey white opaqueness.

SYMPTOMS & TREATMENTS

• Milky cloudiness on skin.

• The best treatment is with copper at 0.2 mg per liter (0.2 ppm) to be repeated once in a few days if necessary.

• Acriflavine may be used instead at 0.2% solution (1 ml per liter). As acriflavine can possibly sterilize fish and copper can lead to poisoning, the water should be gradually changed after a cure has been effected.

• Salt bath 3% solution

• Raising the water temperature to 80° - 83° F for a few days has also been effective.
  
  

1.4 Disease caused by the infection of Chilodonella sp.

• Chilodonella is classified as the most dangerous of the Protozoan parasites and can cause mass mortalities especially in overstocked ponds and aquaria.

• It is between 40-60 microns in diameter.

• It reproduces itself by transverse fission, and the adult has a heart shape appearance

SYMPTOMS

• Opaqueness of the skin, especially between the head and dorsal fin.

• Gills are also attacked and can be totally destroyed, quickly killing the host.

• Affected fish may show classic signs of flashing and rubbing, may hold their fins clamped against their body and appear listless.

• They will also hang at the pond surface and gasp for air in severe infestations.

TREATMENT

• Recommended treatments include Malachite Green

• Formalin

• Potassium Permanganate

• Salt baths at 3%.