Marine Ich (White Spot Disease)

Clinical Pathology

• White Nodules: Distinct, salt-like white pustules (up to 0.5mm) scattered evenly across the body, fins, and eyes.
• Severe Respiratory Distress: Before spots are visible, trophonts ravage the gill lamellae, causing rapid, shallow breathing (tachypnea) and hanging near high-flow areas.
• Flashing: Violent, frantic scratching against live rock or sand substrate to dislodge the parasite.
• Mucosal Hypersecretion: The skin takes on a cloudy, grayish hue due to an overactive immune response producing excess slime.

Epizootiology

1. Pathogen Introduction: The absolute requirement. C. irritans is introduced via asymptomatic carriers, contaminated water, or encysted tomonts on invertebrate shells and live rock.
2. Osmoregulatory Stress: Rapid fluctuations in specific gravity (salinity) or temperature severely depress the innate immune system, precipitating an outbreak.

Eradication Protocols

Because the parasite is protected in 3 of its 4 life stages, treatments must be sustained and rigorous.

• Copper Therapy (Cupric Sulfate/Chelated Copper): The undisputed gold standard for eradication in a sterile hospital tank. Copper ion concentrations must be strictly maintained between 2.0 ppm and 2.5 ppm (depending on the product) for 30 uninterrupted days to kill all emerging theronts. Requires precise digital testing.
• Chloroquine Phosphate (CP): An alternative anti-malarial drug dosed at 15-20 mg/L. Highly effective and less immunosuppressive than copper, but degrades rapidly under UV light.
• Hyposalinity (Osmotic Shock): Lowering the specific gravity to exactly 1.009 for 30 days. This hypotonic environment causes the tomont cysts to rupture via osmotic influx. Requires extreme precision using a calibrated refractometer.
• Tank Transfer Method (TTM): Moving the fish between two sterile, dry-sterilized tanks every 72 hours for 12 days, mathematically outpacing the trophont drop-off and encystment cycle.

Mandatory Quarantine

• Absolute Quarantine: Every fish must undergo a strict 30-45 day quarantine utilizing prophylactic copper or TTM before entering the display tank.
• Fallow Period: If the display tank is infected, all fish must be removed. The display tank must remain completely devoid of fish (fallow) for a minimum of 76 days to starve out all encysted tomonts.