The Ammonia Spike

What’s Happening

Ammonia spikes most often occur during the nitrogen cycle, after adding too many fish at once, or from overfeeding. Even at low levels, ammonia burns fish gills and suppresses their immune system.

Steps to Fix It

1. Do a 50% water change immediately using dechlorinated water. This is the single most important step.
2. Fast the fish for 48–72 hours. Ammonia comes from waste and uneaten food — stop adding to the source.
3. Dose a double dose of beneficial bacteria (e.g. Seachem Stability, Fritz Turbo Start). These bacteria convert ammonia to less harmful nitrite.
4. Retest in 24 hours. If ammonia is still above 0.25 ppm, repeat the water change.

Prevention

• Never add more than 1–2 fish per week during cycling.
• Feed sparingly — only what fish eat in 2 minutes.
• Maintain your filter media; never replace all of it at once.

Track your ammonia readings and get step-by-step crisis alerts in the AquaKeepers app.