Support » Toolbox » Diagnose what’s wrong » Parasite Infection

Our Diagnosis

It sounds like your fish has a parasite infection

How to be sure

Parasite infections come in the form of White Spot (Ich), Slime/Velvet infection and visible parasites, which can be very irritating for the fish. Your fish may act irritable, flicking or twitching in the pond, like it’s trying to scratch itself.

Step 1 – Treat your fish

  • Treat the entire pond using Anti-Parasite Treatment, you can calculate the correct dosage here. Also available, Extra Strength Anti-Parasite specifically for goldfish, Koi and carp. 
  • Also dose with Pond Guardian Tonic Salt to help support your fish’s immune system.
  • Observe the recovery and follow any re-treatment advise on pack or on our dosage calculator page.
  • Finally, give your fish some time to recover. Avoid excessive cleaning or adding new fish.

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

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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