Goldfish Diseases and Treatment

Goldfish are prone to diseases and infections, which cause early death. One of the leading cause of goldfish getting sick is due to poor water quality. Goldfish are hardy fish and can tolerate a wide range of water conditions. In the following article, I have listed some of the common goldfish diseases and treatment methods.  If they are treated on time, they will recover, else, may lead to fatal. If you have spotted something unusual about your fish and think that your fish is sick, it is best to move your fish to a separate tank or a hospital tank. And you must remove carbon from your filtration system, as carbon will absorb medicine, making the treatment of your fish ineffective.

Prevention Is Better Than Cure:

Always Wear a Protective Mask when you go out.
Its better to use a N95 Mask.

Always Wear a safety Goggles.

Make Sure you Wash your hand with a soap for at least 20 Seconds.

Carry A sanitizer when you go out.


List of the most common goldfish diseases and treatment


Goldfish Diseases and Treatment | ich whitespotIch disease, or sometimes called as ick disease is a white spot disease caused by protozoan parasites. These parasite feeds on goldfish tissue and blood penetrating the surface of its skin. Ich can easily be identified; the infected fish will have white spots all over its body.


  • White spot disease is caused due to poor water condition, ich parasites or protozoan parasites, this will affect goldfish with low immunity power leading goldfish to get stressed,
  • This disease is frequently caused by fluctuation of water temperature, or a sudden drop in the water temperature,
  • More often, this disease is transferred from other fish you recently bought; i.e., introducing a new fish to your fish tank that hasn’t been quarantined.


  • The fish will have white spots all over its body; the tank is probably infested with ich,
  • They usually scratch or rub their body against hard surfaces or decorations and breathe heavily.


  • Raise the temperature of your tank to speed up the life cycle of the parasite and leave goldfish body quickly,
  • Adding aquarium salt or non-iodized salt a pound per gallon of water to your hospital tank without mixing it with the water. This will sediment in your bottom of your tank that will kill the ich juveniles. You should not use any filter or aeration in your tank. Caution: [ adding a pound of salt per gallon would kill you fish if dissolved in the water so make sure you don’t dissolve the salt],
  • Quickly after 2-3 minutes, siphon all the salt and do 50% water change without adding any chemicals.

Fin Rot

Goldfish Diseases and Treatment | fin rot tail rot

Fin rot is a disease that causes the fin to turn opaque or blood-streaked. If it’s untreated, it will gradually move to the base of the fin, consequently killing them. Bacteria causing fin rot always are present in the tank or the pond. But, the bacteria only attacks the fish that are unhealthy.


  • The cause of fin rot or tail rot is simply due to poor water quality that causes poor fish health,
  • Another cause of this disease is low water temperature if the fish has been in low temperature for some time.


  • The fin of the fish suffering from fin rot disease will look like they have ragged, torn or red streaks appear in their fins,
  • The goldfish will have missing tale or fins,


  • Always make sure that you have excellent water quality,
  • Add one tablespoon of aquarium salt per gallon of clean water for a salt bath, for a week,
  • If the condition of your fish is not improved, look forward to commercial treatment.
  • Add API Fin and Body Cure to your aquarium.

    Directions: for best results, remove activated carbon or filter cartridge from filter and continue aeration. For each 10 gallons (38 L) of water, empty one packet directly into aquarium. Repeat dose after 24 hours. Wait another 24 hours, then change 25% of aquarium water. Repeat this treatment for a second time, for a total of 4 doses. Then make a final 25% water change and add fresh activated carbon or replace filter cartridge. Treatment may be repeated, if necessary. Note: this medication will cause a slight discoloration of water which can be removed with API BIO-CHEM ZORB or activated carbon. This package treats up to 100 gallons. Four doses required for full course of treatment.

Here is a detailed article on fin-rot disease and its treatment.

Fungal Infection

Goldfish Diseases and Treatment | FungusFungus disease or cotton wool disease is one of the most common goldfish diseases. Like ich, the fungal infection does not affect a healthy fish. If the fish with fungal infection is not treated, it will spread infection from skin to muscle tissue, and fish will eventually die.


  • Fish with a disease like parasitic, ulcer, or open wound will have more chances of getting a fungal infection.
  • The fish with a weak immune system due to poor water quality will contract fungus,


  • The fungus will appear as cotton grows in the body and fins of the fish, the sign of fungal infection.
  • The fish will look uncomfortable and will have a loss of appetite.


  • First, remove your sick goldfish from the main tank to the hospital tank for special treatment,
  • Remove all the chemical media especially activated carbon from your filter,
  • Add aquarium salt, three tablespoons per gallon gradually since a sick fish cannot take this amount of salt,
  • Another method is by adding a solution of methylene blue 3-5mg per liter as a preventive measure,
  • Bathe the sick fish in a solution of one part of copper sulfate to 2 million portions of water for two minutes.
  • To prevent disease breakout use API Melafix.

Velvet Disease

Goldfish Diseases and Treatment | Velvet DiseaseThis disease is called a velvet disease because the infected fish will have light tan velvet coating over their bodies. It is much similar to Ich but much smaller compared to Ich. The velvet disease is also known as Oodinium, Rust disease, or Gold Dust disease. This disease is almost invisible on gold-colored fish and is clear on light-colored fish.


  • Velvet disease is often transferred from other fish you recently bought; i.e., introducing a new fish to your fish tank that hasn’t been quarantined.
  • Velvet usually happens when you use un-sterilized equipment like the net, which is highly contagious,


  • The infected will have whitish-yellow powdery like spots around their skin and later on body and gills.
  • It starts from the back of the body and then spread to on other parts of the body and gills.
  • The infected fish starts to scratch their body onto objects to get rid of parasites.
  • Goldfish that are heavily infected with this disease will have a hazy appearance and will swim horizontally near the surface of the water.


  • Cover the tank with a cloth and turn off the lights of the aquarium and room’s light during the treatment.
  • During the treatment, the water temperature must be at 80 degrees, and you must remove any chemical filter media, i.e. activated carbon.
  • Add 1 and a half tbs. of aquarium salt per gallon of water, the salt should be un-iodized,
  • Use this treatment at least for ten days and see the best result.
  • An alternative to this method is to use copper-based chemical,
  • use one part copper sulfate to two million part of water, immerse the fish in the solution for not more than two minutes,

Anchor worm (Lernaea Cyprinacea)

Anchor Worms are a type of parasite organism that burrows its head into the host body and feeds on its nutrition. These parasites are mostly found behind a pectoral or dorsal fin.


  • This disease is mostly caused by a newly added fish already carrying the parasite in them, or the plant that has larva on them.


  • The early sign if you notice the appearance of a thread-like material attached to goldfish body,
  • Also, goldfish scratching its body against hard surface around the tank,


  • Since the larva or anchor worm are freely swimming in your tank or pond, you need to treat both the tank and the sick fish,
  • Manually remove all the visible worm from fish body suing tweezers,
  • For the treatment of Anchor Worn, Potassium Permanganate is used,
  • Use Potassium Permanganate: 100mg per 2.5 gallons of water for goldfish bath for 30 minutes or remove when the fish becomes stressed,
  • Do regular water change for a week adding 1-2 tbs. of aquarium salt,


Goldfish Diseases and Treatment | ConstipationConstipation is by far the most common illness in goldfish. This disease is caused due to indigestion is goldfish. Constipation is not a disease, but, a condition brought due to poor food quality or inadvertent overfeeding. Indigestion leads goldfish to float upside down.


  • Due to overfeeding or poor food quality,
  • Furthermore, constipation causes air bladder to inflate because air bladder opens into the digestive tract. So, any gas produced from digestion finds its way to air bladder that causes air bladder to swell, that causes fish to swim upside down.


  • The ill fish tends to swim upside down in the surface of the water,
  • The fish will have irregular breathing and lack of movement.


  • The initial step is to stop feeding your fish,
  • Move the sick fish to the hospital tank adding two tbs. Aquarium salt per gallon of water,
  • Don’t feed your fish until it has regained its balance while swimming,
  • Try feeding green pea or green plant food to your goldfish,
  • After your goldfish recovers from constipation, feed your goldfish live or frozen food and vegetable matter.

Hole in The Head (HITH)

Hole in the head disease is a fairly common disease in freshwater fish. HITH mostly affects cichlids, like discus, oscar, flowerhorn, and so on. Hole in the head disease is also known as Head And Lateral Line Erosion (HLLE). No aquarist wants to see the hole in the head disease. If the hole in the head disease is treated at the beginning stage, the fish suffering from HITH disease can survive. If treatment is late, the infection reaches the organs of the fish, destroying the organs, and the fish dies.


  • The exact reason for the hole in the head disease is yet to be discovered. However, the presence of any one of the causative factor may be responsible for this disease.
  • Hole in the Head, HITH, is caused due to Hexamita Protozoa, that is highly contagious.
  • Poor water quality,
  • Vitamin imbalance may contribute to this disease,
  • The condition that creates stress in fish may also increase the cause of this disease,
  • Other reason might be overcrowding of fish, improper nutrition and vitamins, use of activated carbon can cause the disease.


  • Initially, you will notice a small pimple-like substance in the head of the goldfish. The disease starts as a red dot on the head above the eyes.
  • If the environment is poor, and treatment is not initiated, the pimple turns into the hole and gets larger that allows secondary bacteria and infection to develop.
  • Fish stops eating, loses weight, and stays at the bottom of the tank.


  • A fish suffers from a hole in the head disease mainly because of a messed up aquarium water, so the initial stage is to change 75% of your aquarium water every day until it cures. Perfect water is always necessary for the fish to stay healthy.
  • Another treatment is to use Hydrogen Peroxide. Swap the hole with Hydrogen Peroxide, it causes bubbles to form, but you don’t need to worry.
  • Add 250 mg Metronidazole per 10 gallons of water.
  • In cases where secondary bacterial infections are present, you might need additional antibiotics such as Maracyn, Kanacyn, or Furan.
  • Preventing the hole in the head disease is far more comfortable than treating so:
  • Don’t overcrowd your aquarium and feed healthy food.
  • Clean your aquarium regularly or weekly.

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