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Epistylis

Epistylis (colonial protozoan)

Moderate severity

a protozoan that forms fuzzy tufts resembling fungus or ich, thriving in dirty water

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Symptoms

Catching illness early gives the best chance of recovery, so check your fish daily. Fuzzy white tufts that can look like fungus or ich, often on the fins, mouth or wounds, sometimes with a slightly 'sparkly' look. Fish may flash and lose condition. Act promptly if you see several signs together.

Causes

A protozoan that colonises fish (especially in nutrient-rich, dirty water) and feeds on bacteria; it often takes hold on injuries or already-stressed fish. The underlying trigger is almost always stress, poor water quality or a newly introduced animal.

Treatment

Improve water quality dramatically with water changes, and treat with an antibacterial plus a parasite treatment (it differs from true fungus, so antifungals alone often fail). Address any underlying wounds.

While treating, increase aeration, remove activated carbon from the filter, finish the full course even after symptoms fade, and keep the water immaculate. Marine treatments belong in a separate quarantine tank, never the reef.

Prevention

Keep water pristine and low in organic waste, and treat injuries promptly so this opportunist can't establish. The golden rules: quarantine new arrivals, never overstock or overfeed, avoid sudden swings, and keep up regular water changes.

FAQ

What is Epistylis in fish?
A protozoan that forms fuzzy tufts resembling fungus or ich, thriving in dirty water.
How serious is Epistylis?
It is rated moderate severity. Prompt treatment greatly improves the outcome.
How do I treat Epistylis?
Improve water quality first, then use the correct treatment for the cause (see the Treatment section), removing carbon while medicating and completing the full course.
Can Epistylis be prevented?
Yes - quarantine new arrivals, keep water pristine and stable, and avoid stress, which is what lets most diseases take hold.
Will it spread to my other fish?
It is not strongly contagious, but the conditions that caused it can affect others, so review your water quality.

This information is general guidance, not veterinary advice. Consult an aquatic vet for serious cases.

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