Our Diagnosis

It sounds like oxygen levels are low

How to be sure

If you have tested your water and found no problems, and there is no obvious signs of disease, the gasping is likely to be caused by low oxygen in the water. Low oxygen tends to occur when the weather is hot, there is little water movement or the pond is over-stocked with fish. It can also be effected by using treatments.

Step 1 – Treat your fish

  • Treat the pond by adding an air pump, and ensuring pumps and filters are running well. A quick solution to increase oxygen is to add a solar air pump.
  • To ensure there are no underlying, invisible disease, also treat the pond with All In One Fish Treatment.
  • Observe the fish to see if the behaviour subsides. If this does not resolve the issue it is possible the fish have a bacterial gill disease which can be difficult to see. In this case, treat the entire pond using Anti Ulcer and continue to observe recovery (wait 7 days if you already treated with All In One).
  • Finally, give your fish some time to recover. Avoid excessive cleaning or adding new fish. Leave the air pump running as adding treatments can also reduce oxygen levels.

Remember to remove the carbon from your filter prior to dosing with treatment.

Step 2 – Check your pond

  • When fish are sick, always test your pond water for excessive ammonia, nitrite, nitrate or pH imbalance.
  • Treat any unhealthy results to rebalance your water quality and give your fish the best chance of getting fighting fit again.
  • Check all your equipment is working properly – especially filters. Carry out any maintenance needed, or replace faulty or broken parts.


Blagdon fish medications can safely be used with Blagdon water and algae treatments.

If you want to re-dose, or change a fish medication, wait 7 days before beginning the new course.

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