Fish health issue • Bacterial • 🟠 High risk

Columnaris Disease fish health guidance for clubs & fisheries

Columnaris is a serious bacterial infection causing ulcers, fin rot and rapid fish losses in warm water.

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Supports EA reporting decisions • Practical steps for bailiffs & coaches • Junior-friendly explanations
Signs & symptoms • Actions to take • Reporting

Category

Bacterial

Helps you quickly understand whether this is a parasite, viral issue, water quality problem or wider management topic.

Severity

🟠 High risk

Use alongside EA guidance and your own fishery rules to decide next steps.

Notifiable?

No – but still monitor closely

Always follow the latest EA advice on notifiable fish diseases.

Linked species

No specific species linked

Used to surface this guidance directly inside the Clubnest Species Guide.

Scroll down for full guidance, reporting advice and linked species for this condition.
Spot issues early, act quickly
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About this condition

Columnaris is a serious bacterial infection causing ulcers, fin rot and rapid fish losses in warm water.

What is Columnaris?

Columnaris is caused by Flavobacterium columnare and spreads quickly in warm, poor-quality water.

Report Fish Disease or Pollution

If you suspect this condition, see unusual fish behaviour, or witness a pollution incident at your waters, you must contact the Environment Agency immediately. Quick reporting protects your fishery and prevents further fish mortalities.

EA Incident Hotline

0800 80 70 60

24 hours · Free to call

Report an Incident

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