Support » The Fish Doctor » Diagnose what’s wrong » High Nitrite

Our Diagnosis

It sounds like your aquarium has high Nitrite levels

How to be sure

Your test results show high nitrite levels and your aquarium generally looks ok – this is an invisible water quality problem.  Your fish won’t like it – they may appear pale or dark and shimmy, scratch, jump and flick against objects in the aquarium.  Rapid gill movement and breathing at the water surface are also signs of your fish’s discomfort. If visible, the gill membrane may look brown rather than the usual bright red.

Step 1 – Treat your aquarium

  • Complete a 25% water change and re-test after a few hours
  • Add Fast Filter Start to boost the bacteria in your filter to process the extra nitrite.
  • Continue to regularly test your water

Step 2 – Support your fish

  • Dose with Aquilibrium First Aid Salt â€“ to help your fish feel well, while your water quality improves.
  • If your fish are gasping at the surface, increase oxygen levels by adding an air pump.
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