Most Ammonia burn cases I see in beginner tanks are caught late because the early signs are easy to miss under normal lighting. The good news: most cases are treatable at home if you act in the first few days.
What is actually causing it
Ranked by likelihood:
- Stress from poor water — ammonia or nitrite above 0 ppm, or nitrates over 40 ppm.
- Secondary infection — a wound or parasite opens the door.
- Temperature swing — more than 2 °C in a day weakens immunity.
Test the water first; treat the cause, not just the spot. A the Ich (White Spot) Treatment Plan walkthrough makes the numbers obvious.
The symptom
Red gills, gasping at the surface, and clamped fins right after a cycle crash or overstocking.
The treatment
Step by step:
- Move the sick fish to a hospital tank if you can, see our Fungal Infection Treatment Plan guide.
- Raise the temperature slowly to 29 °C to speed the pathogen's life cycle (species permitting).
- Add 0.1% aquarium salt, dissolved first, and keep it stable with a 35% water change every other day.
- Follow the medication label exactly; overdosing does more harm than the disease.
A step-by-step plan
Plan Ammonia burn treatment as four moves: clear ammonia and nitrite, relocate the fish to a hospital tank if you can, apply the medication exactly as labelled near 29 °C, and re-test every other day.
Prevention
Quarantine every new fish for 4 weeks, keep nitrates under 20 ppm, and avoid overcrowding. Stability is the best medicine, a tank that holds its parameters rarely sees outbreaks.
