Parasitic
🟡 Moderate
✓ Treatable
Hole-in-the-Head Disease
🦠 Spironucleus vortens (and/or Hexamita spp.) · Hexamitidae (Diplomonadida)
📋 Overview
The disease presents as pitting erosions around the sensory pores of the lateral line and head. While the protozoa are present in many healthy fish, immunosuppression from poor water quality, vitamin deficiencies, or activated carbon use is thought to trigger clinical disease. Metronidazole (Flagyl) is highly effective.
📊 Key Facts
Causative Agent
Spironucleus vortens (and/or Hexamita spp.)
Agent Family
Hexamitidae (Diplomonadida)
Onset to Peak
weeks–months
Geographic Range
Worldwide in tropical and cichlid aquaria
Transmission Routes
Faecal-oral, contaminated water or substrate
Primary Host
Cichlids (Discus, Oscar, Angelfish), freshwater tropical fish
Vaccine
✗ None / Experimental
🩺 Clinical Signs
Pitting lesions on head and along lateral line, mucus-filled erosions, white-cream faeces, weight loss, colour loss, anorexia.
🔬 Symptoms
🔬
Head pitting lesions
Integumentary Chronic
🔬
Lateral line erosion
Integumentary Chronic
🔬
White/cream faeces
Digestive Subacute
🔬
Progressive weight loss
Systemic Chronic
🧪 Diagnosis
Clinical signs, wet mount of lesion material or faeces showing flagellates.
💊 Treatment
Metronidazole (in food or bath), improve water quality, vitamin supplementation (especially C and D).
🛡️ Prevention
ℹ️ Prevention is the most effective strategy for managing this disease in aquaculture and aquarium settings.
Avoid overuse of activated carbon, maintain pristine water quality, varied diet.