Goldfish Diseases By Symptoms And Treatment

This is a summary of 7 diseases and treatments
Tail or Fin Rot
Copepods, Lice, Anchor Worms
All fish fall sick and are afflicted by disease and problems occasionally. Many goldfish unnecessarily die because their owners don’t recognize the different diseases.

Learning how to detect and diagnose disease in the early stages will greatly improve the outcome.

Recognising symptoms early for treatment intervention you’ll give your sick fish the best chance of recovery

Goldfish are prone to diseases or infections, which can cause early death.

One of the main reasons goldfish get sick is because of a dirty tank or aquarium. When their tank is dirty, filtration, water and oxygen levels become low. This leads to the temperature becoming either too warm or too cold and breathing is made difficult for the fish. The importance of keeping the tank clean can’t be emphasized too much.

#1 Ich

Also known also as freshwater white spot disease or Ichtyopthirius

  • This is caused by a microscopic parasite which is known as the Ichthyophthirius multifiliis
  • The parasites attach themselves to the goldfish which then forms the white spots
  • Symptoms of this disease include
    1. visible white dots covering your the body of the fish
    2. rapid gill movements in later stages of disease and
    3. fish frequently rubbing itself against objects in the tank.


This disease can be treated by vacuuming the gravel and then treating the whole fish tank with salt. Malachite Green treatment and the product API Super Ich Cure are also effective.  Find out more on the links.

#2 Flukes

  • Symptoms of this disease include flashing, irritation, difficulty in breathing and lethargy.
  • With flukes, a gill or body scrape is important to diagnose.


Treat flukes by using Prazi Pro in a fish tank and Praziquantel in a fish pond.

#3 Tail or Fin Rot

  • Tail or Fin rot is also known generally as necrotic loss of fin tissue and is caused by stress and poor environmental conditions.
  • Symptoms of this disease include ragged fins and a hole appearing in the middle of the edge of the fin.

tail or fin rot treatment


Tail or Fin Rot can be treated by melafix, using salt, and hydrogen peroxide bath.

#4 Copepods, Lice and Anchor Worms

  • For diagnosing this disease there’s the advantage that parasites are large enough to be seen with the naked eye.
  • Symptoms of this disease include louse’s eye spots on the bump when watched closely, grey-green to brownish raised spots on the fish.
  • Your fish may be rubbing itself against items in the tank


If possible treat your fish by removing parasites with tweezers then clean the sore with iodine or hydrogen peroxide to prevent another infection.

Potassium Permanganate can be added to the tank water for treatment.

Alternatively treat the whole fish tank with Microbe-Lift Lice  and Anchor Worm Treatment or Dimilin.

#5 Flex

  • Flex is caused by bacterium, although the disease appears as if it is a fungus.
  • Symptoms include cotton like growths. It has also been described as looking like mould.

#6 Constipation

  • Not a disease but painful nonetheless for your goldfish.
  • It’s caused by a diet without variety or by feeding your fish with too many starchy foods.
  • Symptoms of this disease include difficulty passing excrement.


Change your goldfish diet by including more vegetables. Use different varieties like spinach and peas. You might want to try tubifex worms as well.

#7 Dropsy

  • This is a very dangerous disease and to some levels it cannot be treated.
  • Symptoms include swollen eyes, swollen belly and scales that protrude.


For treatment of dropsy and all other goldfish diseases, ideally consult your vet clinic in order to prevent your goldfish from an untimely death. Your vet can do frequent check ups on your goldfish.

If caught early we suggest trying the treatments on the link above.