GUIDES
Ulcer first-response workflow
Ulcers usually involve bacteria plus an underlying stressor (often water quality or parasites). Treat the fish, but also fix what caused it—or it comes back.
1) Stabilize the pond (first)
- Test ammonia/nitrite, pH, KH, temperature.
- Fix any water issues before you do anything aggressive.
- Strong aeration helps healing.
2) Reduce stress
- Minimize chasing/handling unless you’re treating the wound.
- If you must handle: prepare everything first so the fish is out of water as briefly as possible.
3) Treat the wound correctly
- Clean the area gently.
- Remove loose/dead tissue if appropriate (don’t create a bigger wound).
- Apply a suitable topical approach and protect the area.
- Return fish to clean, stable water.
4) Address the root cause
- If multiple fish are flashing/rubbing: parasites may be involved.
- Use the parasite workflow (includes a safe “shotgun” option): Parasites guide →
- Maintain stable KH/pH (healing is slower with instability): KH/pH guide →
When you need urgent help
- Rapidly worsening ulcers, widespread redness, severe lethargy, or pineconing.
- Fish not righting itself, or severe respiratory distress.
- At that point: isolate if possible, stabilize water, and seek experienced help quickly.