Common diseases that can affect Nile tilapia (Oreochromis niloticus)
- Columnaris disease (Flavobacterium columnare)
Signs: white or grayish cotton-like patches on skin, frayed fins, mouth lesions, ulcers, lethargy.
Cause & conditions: bacterial; often stress-related, worsened by poor water quality and high temperatures.
Management: improve water quality, reduce stocking density, treat with appropriate antibiotics under veterinary guidance, topical antiseptics in hatcheries.
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- Streptococcosis (Streptococcus spp., Enterococcus spp.)
Signs: erratic swimming, loss of appetite, exophthalmia (pop-eye), hemorrhages, ascites, high mortality.
Cause & conditions: bacterial; often occurs in crowded ponds and warm water; can spread rapidly.
Management: good biosecurity, vaccination where available, antibiotics based on sensitivity testing, reduce stressors.
- Aeromonas infection (Aeromonas hydrophila, A. sobria)
Signs: ulcers, hemorrhages on skin and fins, internal organ damage, septicemia.
Cause & conditions: opportunistic bacteria; linked to poor water quality, injuries, and stress.
Management: water quality control, wound prevention, antibiotics after diagnosis.
- Ichthyophthirius multifiliis (Ich or white spot disease)
Signs: small white cysts on skin and gills, flashing, increased mucus, respiratory distress.
Cause & conditions: protozoan parasite; spreads quickly in crowded tanks and ponds.
Management: hyposalinity or other approved treatments, raising temperature carefully to speed parasite lifecycle, quarantine new fish.
- Gill flukes and skin flukes (Monogenean parasites)
Signs: respiratory distress, rubbing against surfaces, visible flukes or increased mucus on gills.
Cause & conditions: direct life-cycle parasites favored by poor hygiene and high stocking densities.
Management: freshwater baths, antiparasitic treatments and improved husbandry.
- Viral diseases (e.g., Tilapia Lake Virus, TiLV)
Signs: variable—lethargy, skin lesions, eye problems, high mortality; diagnosis requires lab tests.
Cause & conditions: viral; serious outbreaks can devastate farms.
Management: strict biosecurity, movement controls, surveillance; no specific antiviral treatment.
Prevention summary: maintain water quality, appropriate stocking densities, good nutrition, quarantine new stock, monitor health regularly, and consult a fish health specialist for diagnosis and treatment.