Costia - Ichthyobodo fish disease

Costia - Ichthyobodo

1. General description

Causes of this disease are flagellates. There are 2 species which attack the fish but Ichthyobodo necatrix is responsible for disease in most cases. The parasite is too small to be seen with the naked eye. It attaches to the skin, fin rays or gills of the host and it feeds contents of the epidermis cells. The parasite very quickly reproduces by binary fission in favorable conditions what ultimately leads to death of the host. Speed of reproduction depends on water temperature and pH. 25-28°C and pH=4.5-6.0 are the most conductive conditions. This parasite can live up to a few hours without the host. It attacks mostly the fry but adult fish may be vectors this parasite.

2. Type of the disease

This disease is caused by parasites.

3. Cause of the disease

Causes this disease are flagellates from Ichthyobodo genus.

4. Favorable circumstances for development of the disease

• stress
• bad water conditions
• too much fish in aquarium
• weakened immune system of fish
• other disease – this parasite may lead to secondary infections

5. Common symptoms of the disease

• excessive secretion of mucus
• pale colours – milky-gray coating often appears
• fish scrape against various elements
• loss of appetite
• rocking from side to side
• gills covered by mucus (when the parasite attacked the gills)
• breathing problems (when the parasite attacked the gills)
• redness of the skin and even open injuries

6. Types of the treatment

A method of treating depends on a stage of the disease. We need treat all aquarium occupants in a separate tank. We don't have to disinfect the general aquarium because all parasites without the host will die after 24 hours. We may prophylactically increase water temperature up tu 32-34°C for a period of two days.

6.1. Treatment for mild and moderate stages of the disease

There isn't redness of the skin or open injuries in this stage. We may use selected one of the following treatments when the gills of the fish aren't damaged:

• increasing water temperature below 30°C for a period of minimum 4 days (the parasites will die on this temperature);
• bath in 38% formalin - we add 2ml per every 10l and we keep there the fish for 30 minutes;
• bath in trypaflavin - we add 10mg (1ml) per every litre of the water and we keep there the fish up to 2 days;

When we suspect damaged gills:

• short-term bath in salt - up to 20 minutes for a period of 7 days, we dose 20g of salt per every litre of water,
• long-term bath in salt – up to a few days, we dose 4g of salt per every litre of water.

6.2. Treatment for advanced stage of this disease

• bath in copper sulphate – 0,2 mg per every litre of the water, we keep the fish every day (minimum 4 days) for about 30 minutes.

We need gradually remove all drugs from the water after fish recovery. So we do systematic a partial water changes.

7. Comments about this disease

• This parasite commonly lives in the aquarium water. It isn't dangerous in small amounts and then it doesn't cause the disease. Everything is changing when the fish have weakened immune system, wrong diet and poor water quality.
• The parasite attacks only weakened fish, especially the fry. Then it very quickly reproduces and leads to death within a week.

8. Prevention

• quarantine for new fish, plants and other animals
• prophylactic baths for new fish
• adequate water parameters
• reduction stressful situations for fish
• properly number of fish, plants and other animals