Hexamita fish disease

Hexamita fish disease

1. General description

Visible symptoms of the disease (skin defects around fish head) occur in advanced stage of this disease. Presumably causes of this disease are 3 species of parasites: hexamita salmonis, hexamita truttae and hexamita intestinalis. They live and feed of organic wastes and they get to fish digestive tract with them. Reproduction of these parasites inside the fish depends on its immune system. The parasites attach to the wall of upper intestine their flagella. When fish immune system is weakened then the parasites rapid reproduce. Then they destroy intestinal mucosa and they expand to other internal organs. The parasites expand to fish head most of all. There they gradually damage tissues which rot. The skin cracks and there appears abscesses and open wounds.

The most effective method diagnosis is observation of fish intestine under a microscope (in magnification 200-400 times larger). The flagellates are well visible in this magnification – they move fast and unequally.

2. Type of the disease

This is parasitic disease.

3. Cause of the disease

Causes of this disease are flagellates from Hexamita genus.

4. Favorable circumstances for development of the disease

• stress induced by:
• - oxygen-poor water
• - high level of nitrites
• - too much fish in aquarium
• - mechanical injuries
• - careless handling of the fish
• - wrong diet
• - malnutrition
• contacts with infected excrement

5. Common symptoms of the disease

• white, jelly like, mucous excrement (they appear when a fish feeds and behaves normally)
• zmiany w zachowaniu ryby: ukrywa się, izoluje, nie reaguje, itp.
• changes in behavior of the fish: it hides, isolates, doesn't react etc.
• loss of appetite
• darkening of skin pigmentation
• loss of weight but the belly is bloated and the head falls down
• marks on the head which transform into abscesses and open wounds (wholes)

6. Types of the treatment

6.1. Aquasan-S preparation from Zoolek company.

We need dissolve capsule in 0.2 litre warm water before application. We dose 1 capsule per every 50l water for disinfectant bath. We dose 1 capsule per every 100l water for preventive bath. This preparation isn't dangerous for plants.

6.2. Metronidazole.

We need give directly this drug orally or for food. Then the medicine is the most effective.

• orally dosage: 0.05mg the drug per every gram of fish weight for next 5 days, once or twice per day;
• dosage with dry food: every 0.5kg food we mix with 2 teaspoons the drug (the drug should be powdered) and we use fish oil as binder. This mixture we give the fish for next 5 days, 2-3 times per day. We feed fish only this amount of food which they may eat by a few minutes. We can freeze this mixture. The sick fish we should feed only food with medicine.

When the fish don't eat we may do curative baths. Then we dissolve the drug in warm water and we dose 5mg per every litre of the water. We do 3 times this bath every other day.

6.3. Hexa-ex preparation from Tetra Medica company

We dose 1 tablet per every 50l water. The curative bath we do for next 5 days. After this time we filter the water from aquarium through activated carbon and we do a partial water change in purpose of removal the drug from the water. We don't use this medicine together with other drugs/preparations.

7. Comments about this disease

• Discus and big cichlids (e.g. oscar fish) are very sensitive to this disease.
• The skin lesions are often attacked by bacteria and viruses and we have to cure few diseases in the same time.
• Symptoms of this disease are often confused with symptoms caused by nutrient deficiencies or dietary imbalances (especially vitamin C deficiencies).
• Hexamita disease is often secondary infection caused by nutrient deficiencies or dietary imbalances.

8. Prevention

• 4-6 weeks quarantine for new fish
• adequate water parameters
• reduction stressful situations for fish
• systematic partial water changes
• systematic cleaning of substrate and filter
• enrichment of fish food with vitamins and microelements