Goldfish Hole in the Head

You are probably familiar with the popular goldfish and you may have even adopted one as a pet. But did you know that goldfish are quite sensitive creatures? One condition that goldfish can develop is hole in the head, which is also known as head and lateral line disease.

This article will look at the causes, symptoms, and treatments for hole in the head disease in goldfish.

What is a hole in a goldfish’s head?

Hexamita is colloquially known as “head hole disease” because one of the most characteristic and noticeable symptoms is the presence of round pits or holes that form on the fish’s head. It’s caused Hexamite Parasite, which is a flagellar protozoan. The disease is also known as “head and lateral line erosion”. It primarily affects freshwater fish, especially goldfish and cichlids.

Although the Hexamita parasite can infect both wild and captive fish, it is much more common in the latter. This is likely because captive fish are often kept in cramped and unsanitary conditions, making them more susceptible to infection. Fish tend to have stronger immune systems and are less likely to contract the disease in the wild.

The parasite Hexamita enters the body of the fish through the gills, enters the intestines and multiplies. The parasite then damages the intestinal mucosa, leading to a number of serious health problems, including malnutrition, dehydration, and death.

Risk factors: What causes hexamite?

Several different factors can increase the risk of developing hexamite in fish. This includes:

Poor water quality

One of the most common risk factors for Hexamita is poor water quality. This is often seen in captive fish kept in small cramped tanks with poor filtration. This creates ideal conditions for the growth, reproduction and spread of the parasite.

Other elements of poor water health include high ammonia and nitrite levels and low oxygen levels. Under such conditions, fish are much more stressed and their immune systems are weakened, making them more susceptible to disease.

To keep your fish healthy and not infected with Hexamita, it is very important to maintain good water quality in the aquarium. This includes regular water changes, using a quality filter, and keeping ammonia and nitrite levels at 0 ppm.

Poor quality diet

Another common cause of hole in the head disease is malnutrition. Just like us, goldfish and other freshwater fish need a well-balanced diet to stay healthy. A diet lacking in certain vitamins and minerals can weaken the immune system of fish and make them more susceptible to disease.

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Providing a quality and varied diet is especially important for goldfish as they are prone to developing hexamite. This is due to the fact that goldfish are omnivoreswhich means they need both plant and animal matter to stay healthy.

Feeding goldfish the wrong or inadequate diet is one of the surest ways to get sick. To avoid this, it is important to provide them with a varied diet that includes both fresh and frozen foods. You can also try one of these fish food replacements.

Crowded Conditions

Crowded tanks are a source of great stress for fish, suppressing their immune systems and making them more susceptible to disease. This is one of the reasons Hexamita is so common in goldfish.

Spirogyra water surface and water inside
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Many fish farmers mistakenly believe that goldfish can be kept in a tiny bowl, when in fact they require at least 10 gallons of water per fish. If you are keeping goldfish, it is important to give them enough space. Nothing stresses a goldfish more than an overcrowded aquarium, which can quickly lead to Hexamita.

Crowding also causes additional stress because it is difficult for fish to find food. When fish are constantly competing for food, they become stressed, which leads to many health problems, including Hexamita. Territorial disputes also common in overfilled tanks resulting in bodily injury.

Symptoms of a hole in the head

Having discussed the causes of Hexamita, let’s look at some of the more common symptoms.

The presence of holes in the head

The first and most common symptom of Hexamita is the presence of pits on the head. These small, crater-like lesions are caused by the parasite eating away at the fish’s skin. These pits may be barely visible in the early stages, but as the disease progresses, they take on a more obvious hollow appearance.

A good way to tell if your fish has Hexamita is to look at those little pits on its head. If you spot any, take the fish to a veterinarian or the nearest fish store for a diagnosis.

When in doubt, it’s always best to play it safe and check the fish. Timely diagnosis can decide if your fish will recover from Hexamita.

Erosion along the lateral line

The lateral line is a series of pores running along the entire length of the fish’s body. These pores are connected to nerves and are used by fish to detect movement in the water.

In fish with Hexamita, these pores are often worn out and inflamed. You will notice visible ulcers along the lateral line, which can be quite painful for the fish. In severe cases, the entire lateral line may be destroyed, leaving the fish’s body open to infection.

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The effects of lateral line erosion are more than just cosmetic. This important sensory organ allows fish to navigate in the water. They are easy prey for other fish or even animals that enter the aquarium without it.

Loss of appetite

goldfish eating

Another common symptom of Hexamita is loss of appetite. This may be caused by the presence of a parasite in the intestines of the fish, which interferes with its ability to properly digest food. In some cases, the fish may stop eating altogether.

Loss of appetite can have a number of other causes, so it is important to rule out any other potential problems before attributing them to Hexamita. If your fish is not eating, the first thing you should do is check the quality of the water. Ammonia and nitrite levels, even slightly elevated, can cause fish to lose their appetite.

If the water quality is okay, then your fish is probably sick and you should take it to the vet or fish store for a diagnosis.


The last and most common symptom of Hexamita is lethargy. This is when the fish becomes lethargic and stops swimming as usual. In some cases, the fish may stop swimming altogether and simply lie on the bottom of the aquarium.

Like loss of appetite, lethargy can have a number of causes, so it is important to accurately diagnose your fish before associating it with Hexamita. However, if your fish is showing more obvious symptoms such as head dimples or blurry lateral lines, then it is likely that Hexamita is the cause.

Treating a goldfish hole in the head

holding a goldfish

Hexamite is rarely fatal, although it can cause permanent injury if left untreated. In most cases, the disease can be cured with a course of antibiotics. Here are some things to keep in mind when treating Hexamita:

Maintain ideal tank conditions

The most important thing to remember when treating Hexamita is to maintain good water conditions. A less-than-ideal aquarium environment can stress the fish and make them more susceptible to disease. Your goldfish should never live in bad living conditions that make them sick.

A great way to keep your aquarium clean is to change 25-50% of the water weekly. This will remove any buildup of toxins in the water and keep your fish healthy. In addition to water changes, you should also vacuum the gravel at the bottom of the tank to remove any uneaten food or waste.

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Tank size also plays a role in Hexamita. Goldfish are large fish and need a lot of room to swim. A good rule of thumb is to have at least 10 gallons (37.9 L) of water for every goldfish.

Fish affected by quarantine

If you have more than one fish in your aquarium, it is important to quarantine the affected fish in a hospital aquarium. This serves two purposes: preventing the spread of diseases and facilitating the treatment of fish.

Goldfish in a bag

In a hospital aquarium, you can maintain ideal water conditions and treat your fish with antibiotics without worrying about the other fish in the tank.

You will need a 10 gallon (37.9 L) tank, an air pump, an air tube, and a foam filter to install the hospital tank. It would be helpful if you also used a dechlorinator to remove chlorine from your tap water. Once the tank is set up, you can add the affected fish and start treating them with antibiotics and other medications.

Medication administration

Hexamita is a parasitic infection, so antibiotics are the most common course of treatment. The two most commonly used antibiotics for Hexamita are metronidazole and nitrofurazon.

These antibiotics are available in both oral and injectable forms. In the first case, you will put the medicine in the gel food and feed it to your fish. In the latter case, you will need to take the fish to the vet for an injection.

Although not a bacterial infection, antibiotics may also be needed if a secondary infection has developed. Consult your veterinarian for the best course of treatment.


Goldfish head hole disease is a common disease that affects goldfish, but fortunately it is also treatable. Prevention is the best form of treatment, but the next best thing you can do if your fish has contracted a disease is to act quickly and decisively. We hope this article has been helpful in this regard. Understanding the causes, symptoms, and course of treatment for goldfish disease is the first step to effectively treating your goldfish.

If you have any unresolved questions or concerns, please feel free to leave a comment below or contact us directly. We are always happy to help! And do us a favor: if you found this article helpful, please share it with your angler friends! Happy fishing!

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