Treating skin ulcers in fish (how to). – YouTube

Skin ulcers in fish can be due to a large variety of causes including water quality, immunosuppression, stress, bacterial infection and a host of parasitic diseases.

Just this week I’ve attended several cases of skin ulcers in fish that were caused by multiple factors.

  • Case 1: Koi with skin flukes as primary cause.
  • Case 2: Ammonia (and later, nitrite) issues due to ineffective biofilter.
  • Case 3: Low pH and copper toxicosis due to lack of buffers and use of hot water from the tap.
  • Case 4: Straight bacterial infection.

The key to a cure is to first, get the right diagnosis prior to treating.


Thus, to treat merely with antiseptics (e.g. Potassium permanganate) or antibiotics may not achieve a cure. You’d end up frustrated, and prolong the inevitable; fish will continue to suffer and die.

In this case we were able to diagnose skin flukes (on microscopic exam) as the primary cause of skin ulcers in the pond of koi fish. So, in addition to antibiotics and supportive therapy, the fish were also treated for flukes.

See how I treated this individual <


The Powder Gel I used is available from <>. I’ve used it on many species including freshwater and marine turtles, seahorses, koi, goldfish, marine sharks and more. The only species it hasn’t worked in was the wobbegong shark. A must-have for every fish ulcer treatment.

I’d like to thank my client for allowing me to share this case with you.

Yours sincerely,

Dr Richmond Loh
DipProjMgt, BSc, BVMS, MPhil (Pathology) Murdoch, MANZCVS (Aquatics& Pathobiology), CertAqV, CMAVA, NATA Signatory.
THE FISH VET, Perth, Western Australia.
Veterinary Medicine for fish.
E: thefishvet
P: +61 (0)421 822 383



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