Marine Ich / Cryptocaryoniasis

About this condition

An infection caused by the parasitic ciliate Cryptocaryon irritans, which attaches to the skin and fins of marine fish, producing white spot-like lesions. It is highly contagious and can spread rapidly throughout a tank.

Common symptoms

• White salt-grain-like spots on the body and fins
• Vigorous scratching against rocks or substrate
• Clamped fins and rapid breathing
• Loss of appetite and lethargy

Common causes

• Infestation by Cryptocaryon irritans (marine white spot parasite)
• Introduction of new fish without prior quarantine treatment
• Stress from sudden water temperature fluctuations
• Weakened immunity due to overcrowding or poor water quality

Prevention (husbandry & daily care)

Always quarantine newly purchased fish in a treatment tank for 2-4 weeks. Maintain stable water temperature, water quality, and salinity to minimize stress on fish.

Related species guide

When to see a vet

What can a specialist store do?

Since veterinary clinics experienced with marine fish are limited, consulting a specialist marine aquarium store or experienced marine aquarist is recommended as a first step. Guidance on appropriate quarantine duration, freshwater dip procedures, and specialist-supervised treatment options can be obtained.

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Other conditions in this animal

The same condition in other animals