Aqua

• Genus Dactylogyrus


  Parasitic copepod that infects Cyprinid (carp) fishes
• Dactylogyrus


  • Four-lobed head with four eye spots on the anterior end
  • 7 pairs of marginal hooks on the posterior end
  • Opisthaptor with one conspicuous pair of large hooks
  • Adult structure reaches up to 2mm in length
• Common Dactylogyrus species in the Philippines

  • D. vastator
  • D. anchoratus
  • D. extensus
• Dactylogyrus life cycle


  1. Eggs released in water hatch in 4 days at 20°C

  2. Oncomiracidium must find host within 6-8 hours to survive
• Horizontal transmission


  Transmission between fishes through physical contact in crowded environments or when flukes are present in the water
• Dropsy


  Buildup of fluid inside the body cavity or tissues of a fish
• Dropsy


  • Symptom rather than a disease
  • Can indicate bacterial infections, parasitic infections or liver dysfunction
• Dactylogyrus is hermaphroditic and capable of releasing fertilized eggs
• Freshwater fish


  • Inhabit an environment with lower density compared to their bodies
  • Water continuously attempts to equalize the fish's density through passive diffusion, predominantly affecting the skin and gills
  • Kidneys and gills work to eliminate excess water and expel it along with other waste
• Pathological changes in Dactylogyrus infection

  • Hyperplasia of gill filaments
  • Clubbing appearance due to fusion of gill lamellae
  • Tissue loss where parasite attached
  • Increased haemorrhage with high infection intensity
• If kidneys or gills malfunction, effective removal of water is hindered, causing the fish to absorb excessive amounts
• This leads to the saturation of all tissues, potentially resulting in organ failure unless prompt and proper treatment is administered
• Mortality in infected fish occurs due to impairment of the respiratory system
• Early detection, diagnosis, and treatment offer the best prospects
• Diagnosis of Dactylogyrus


  • Observing parasites in wet mounts of gill tissues
  • Dactylogyrid flukes have 4 eye spots and visible eggs
• Causative agents of dropsy

  • Stress induced by poor water conditions, insufficient diet, aggression from tank mates, tumors, parasites, viruses, and bacteria
  • Prolonged stress results in compromised immune function, facilitating secondary infections
• Treatments for Dactylogyrus


  • Masoten bath 25-30 g/l for 5-10 min
  • Quinine hydrochloride 30 ppm bath
  • Trichlorfon 0.25-3.0 mg/l for 3 days
  • Praziquantel 1 g per 378 L water, repeat 2 more times 4-5 days apart
• Popeye


  • Type of disease that causes a fish's eye to protrude out and appear murky or white
  • Caused by swelling from fluid seeping into region behind eyeball, building up pressure and pushing eye outward
• Prophylaxis for Dactylogyrus


  • Maintain appropriate fish diet
  • Disinfect with calcium oxide before stocking
  • Quarantine new fish
  • Dry out ponds before introducing fish
• Popeye can also cause systemic symptoms like changes in behavior, loss of appetite, clamped fins, rough scales, and body swelling
• Genus Caligus


  Parasitic copepod that latches onto various fish species, primarily in marine and brackish waters
• Popeye is a serious condition requiring immediate treatment, as it can lead to loss of eyesight or eye decay
• Caligus


  • Oval and flattened shape, up to 3 mm long and 1.6 mm wide
  • Four pairs of legs
• Host species for Caligus

  • Salmon
  • Tuna
  • Yellowtail
  • Milkfish
• Popeye disease in fish

  • Eyes become enlarged and protrude unnaturally from the socket
  • Eyes may become hazy, bleeding, or discolored
  • Eyes might burst altogether in severe cases
• Caligus life cycle


  1. 3 planktonic stages (2 nauplius, 1 copepodid)

  2. 5 parasitic stages (copepodid attaches, 4 chalimus stages)
• Popeye is a serious condition that requires immediate care
• If only one eye is affected (unilateral)


  It is likely caused by an injury rather than a problem with the water chemistry
• Clinical signs of Caligus infection

  • Clawing or flashing
  • Lumpy body surface
  • Excessive mucus production
  • Lethargy
  • Loss of appetite
  • Listless behavior
  • Erratic swimming
  • Erosion of skin and muscles
  • Pale gills (anemia)
• If both eyes are affected


  It is usually caused by an infection
• Secondary bacterial or fungal infections may occur in heavily infected fish, resulting in high or mass mortality
• Numerous organisms, such as bacteria, fungus, and parasites, can cause popeye infection
• Diagnosis of Caligus


  • Visually inspecting fish for presence of adult parasites
  • Microscopic observation of skin scrapings for eggs or motile copepodid stages
• Popeye can also be caused by poor water quality, and fish that are more susceptible will be impacted first
• Treatments for Caligus


  • Freshwater baths
  • Chemical treatments (parasiticides)
  • Physical removal of adult parasites
  • Emamectin benzoate
• Pathogenesis of popeye


  Swelling of the fish's eye is caused by tissue fluid leaking into the region behind the eyeball, building up pressure and forcing the eyeball outward
• Preventive and control methods for Caligus

  • Provide sufficient water exchange
  • Freshwater immersion (10-15 min)
  • Hydrogen peroxide bath (150 ppm, 30 min)
  • Formalin bath (200-250 ppm, 1 hour)
• Popeye is most frequently caused by continual exposure to chronically poor (rather than acutely lethal) water conditions
• Popeye is most often seen in aquariums where messy fish are kept in unhygienic conditions, typically goldfish and large cichlids
• There are no diagnostic tests or procedures used to determine fish popeye