can you cure hole in the head disease?

How To Treat Hole in The Head Disease in Angelfish

(Last Updated On: May 24, 2021)

Hole in the head disease is one of the most common angelfish health conditions. It’s characterized by holes that appear in an affected fish’s head that sometimes turns white and produces discharge. Angelfish with this disease will become sick due to a loss of appetite and resulting infections.

Hole in the head disease, which is also known as Hexamitiasis, is caused by Hexamita – a flagellate parasite. Studies suggest that activated carbon can also bring on the condition. The most noticeable sign of hole in the head is lesions on the head, which later turn into cavities. Hole in the head disease in angelfish can be treated by maintaining good tank hygiene, reducing stress levels, improving the diet, and using a medication like Metronidazole.

Like many other fish-related diseases, poor tank management is a leading cause of hole in the head in angelfish. This condition is treatable if diagnosed early. If it’s left untreated for too long, there won’t be a cure.

What Is Hole in The Head Disease in Angelfish?

Hole in the head disease is also known as head and lateral line erosion (HLLE) and Hexamitiasis. It’s a common parasitic disease that affects certain species of saltwater and freshwater fish, including cichlids, discus, and oscar fish. As cichlids, angelfish are prone to this condition.

While hole in the head disease doesn’t have an exact known cause, it’s theorized that Hexamitiasis is caused by the flagellate parasite, Hexamita.

Interestingly, the disease doesn’t start at the head but inside the intestinal tract. It then spreads to the gall bladder, kidneys, and abdominal cavity. It’s not until the disease gets more advanced that it reaches the head.

As we’ve already mentioned, there’s also a theory that there’s a link between the use of activated carbon and hole in the head disease. The North American Journal of Aquaculture examined the relationship between the two. Researchers exposed 12 fish to lignite carbon and discovered that they all developed hole in the head disease within 3 months.

While this idea is still relatively unexplored, it’s thought that carbon removes some of the good nutrients that fish require, increasing harmful Hexamita organisms present in the intestine.

Angelfish with hole in the head disease develop lesions that appear on their head and flank. This is where the name comes from. Sometimes, the lesions open up to release white discharge containing parasitic larvae.

When the disease reaches this stage, it becomes dangerous. Secondary bacterial and fungal infections can set in, causing sickness and death.

What Does Hole in The Head Disease Look Like?

Hole in the head disease produces clear, white lesions in the head and lateral line, starting at the sensory pores. The lesions look like ulcers, and it’s thought that this is because the parasite blocks blood vessels, causing the tissue to die. Ulcers form where healthy tissue once appeared.

Lateral lines are faint lines that run down the angelfish’s sides. The line starts from the gill and ends at the base of the tail.

how to get rid of hole in the head disease

Is Hole in The Head Disease Contagious?

There’s no evidence that hole in the head disease spreads from fish to fish. However, the disease is mostly caused by improper living conditions and poor nutrition, which all angelfish in the tank are exposed to.

This makes it likely that, if one angelfish suffers from hole in the head disease, other fish in the tank do too. As a result, it’s wise to assume that all fish are vulnerable, even if only one exhibits symptoms.

When you deal with the problem, it’s a good idea to separate the angelfish with the parasite from the ones that don’t seem to have it so that they can recover without the risk of aggressive fish, making them more stressed.

What Are The Causes of Hole in The Head Disease in Fish?

We’ve already established that the flagellate parasite, Hexamita and activated carbon are the main reasons for hole in the head disease, but many other factors cause it to appear in the tank in the first place.

There isn’t one cause of hole in the head disease, making it hard to find the cause of the problem. Also, most angelfish carry the Hexamita parasite, but it doesn’t affect them under healthy conditions. It can develop at any time.

These are the most common causes of hole in the head disease from occurring in the first place:


Fish become stressed for several reasons, such as territorial or aggressive fish in the tank and poor tank hygiene.

Integrative and Comparative Biology explains how stress factors that are overly severe or long-lasting threaten the fish’s health. Stress can affect:

  • Metabolism
  • Hydromineral balance
  • Breathing
  • Immune system
  • Cardiovascular functions

When an angelfish is stressed, it releases hormones, including adrenaline and cortisol, to give it the energy to escape. Adrenaline affects a fish’s ability to balance the body’s salt and water, while cortisol reduces the immune system’s effectiveness. This makes the fish more prone to diseases.

Poor Water Quality

Unhygienic conditions inside the tank are a breeding ground for harmful bacteria. Decaying waste matter, dead fish, and rotting food increase ammonia and nitrite levels in the tank’s water. Over time, this can seriously affect an angelfish’s health.

Eventually, the fish’s immune system weakens. It also becomes overly-stressed by the low water quality inside the aquarium and, as a result, ends up more seriously affected by bacteria and infections.

If harmful bacteria are allowed to grow and accumulate, they can disrupt the tank’s ecosystem. They also kill off all the beneficial bacteria that keep things healthy and clean. Over time, the angelfish deteriorate and get sick more quickly than if the tank maintained acceptable hygiene levels.

Improper Nutrition

Diet is a commonly accepted cause of hole in the head disease. If angelfish don’t have access to vitamins and minerals required to keep them healthy, their bodies degenerate.

A lack of calcium, phosphorous, and vitamins C and D contributes to the development of hole in the head disease. A low-quality diet or infrequent feeding causes this. 

The MSD Veterinary Manual explains how it’s dangerous to assume that what’s suitable for one species of fish is good for another. While you may have kept fish before, angelfish need high-quality flakes, frozen seafood, and the occasional live food that allow angelfish to hunt.


When new fish are added to the tank, they bring new bacteria with them. The immune systems of some angelfish can’t cope with being exposed to unfamiliar bacteria and become unwell. 

Over-crowding also causes ammonia and nitrite in the tank to rise to harmful levels. Bacteria can’t neutralize these toxins fast enough, causing fish inside the tank to become sick.

As a result, fish become stressed and anxious, causing the immune systems to become weak and more susceptible to hole in the head-causing bacteria.

To prevent over-stocking your tank, use the water surface area rule as a guide, stocking 1 inch of fish for every 12 square inches.

Old Age

Older angelfish are more prone to developing hole in the head disease. Their bodies start to become weaker and have greater difficulty fending off infections and diseases. This leaves their immune systems more delicate and less likely to an survive attack.

Older angelfish are less likely to survive secondary infections for the same reasons. They’re often more severe as they attack the already-weakened immune system.

Early Signs of Hole In The Head Disease in Angelfish

There are 3 noticeable stages to hole in the head disease. As the disease develops and gets worse, you’ll notice your angelfish becoming noticeably unwell. Fish that have been contaminated with Hexamita display the following symptoms:

Stringy Feces

Angelfish with hole in the head disease produce white feces. It may also change shape to appear long and stringy. White poop is feces with no food in it. It’s also a sign that intestinal parasites are present inside your angelfish’s body. In the case of hole in the head disease, this is Hexamita.

When white feces result from hole in the head disease, it means your fish isn’t eating. Parasites cause a loss of appetite, so affected angelfish likely refuse to eat their food.

White, stringy poop is also a symptom of a poor diet, which is a leading cause of hole in the head disease.


As the angelfish struggle to eat and nourish themselves, they become emaciated and look ill. Hole in the head starts in the intestines, so it can become painful for angelfish to eat, causing them to stop altogether.

As a result, starvation will kill the fish if the parasite doesn’t first. It simply depends on the severity of the disease.


Angelfish that are unwell with hole in the head disease isolate themselves in the corners and bottom of the tank.

Angelfish hide their illnesses to keep themselves safe from predators and larger fish that bully them. Angelfish can only pretend to be well for so long, so isolating themselves and hiding in plants allows them to feel somewhat protected.

Fish also have an instinct to stay away from the rest of the school to protect them, too, especially with contagious bacterial diseases. While Hexamita isn’t necessarily infectious, it’s still dangerous and causes an angelfish’s survival instincts to kick in.

Loss of Color

Hole in the head disease causes angelfish to become white and colorless. Angelfish are naturally colorful, so color loss is instantly noticeable.

The fins and tail can also become frayed as the body comes under attack from the hole in the head-causing parasite.

Enlarged Sensory Pores

One of the most apparent signs of hole in the head disease is the characteristic lesions of the sensory pores, appearing on the head and trunk.

Once the disease reaches the worst stages, deep holes or pitted wounds appear on the angelfish’s head and lateral line. They start off pinhole-sized and spread outwards. Multiple spots can also occur in one place.

Discharge containing parasitic larvae sometimes releases from the holes. This gives the holes a whiteish look and looks a lot like stringy mucus. However, it’s important to note that not all fish get white lesions until the later stages, so hole in the head often goes undiagnosed until it’s too late.

best treatment for hole in the head disease

How To Get Rid of Hole In The Head Disease in Fish

A burning question you probably have right now is, “can you cure hole in the head disease?” The answer is yes, but only if you’ve caught it early. Once holes in your angelfish’s head begin to appear, the chances of survival become slim and you’re probably too late.

To clear up hole of the head disease, you’ll need to attack it from multiple angles. There is no overall cure, but combining several treatments should kill the parasite and improve your angelfish’s health and wellbeing. The best treatments for hole in the head disease are as follows:

Clean The Tank

Once you’ve identified that your angelfish have hole in the head disease, you’ll need to act quickly to improve the tank’s conditions and the quality of the water.

Test the water to check the pH levels. You’ll also need to find out whether ammonia and nitrite are present at unsafe levels. If so, the water is likely making your fish stressed and unwell and will speed up the fatality of hole in the head disease. To clean your tank, follow these steps:

  1. Replace 10% – 20% of the tank’s volume with clean, fresh water
  2. Dechlorinate the water before adding it in and scrub the sides of the tank to remove harmful bacteria and build-up
  3. Remove decaying matter, like dead plants and rotting food. Check for any dead angelfish.
  4. Use a siphon to clean the tank’s substrate of rotting matter
  5. Clean the filter using the tank’s water to remove gunk and slime. Don’t run it under a faucet, as you’ll need to preserve the beneficial bacteria that are present

Once you’ve cleaned the tank, repeat the process every other week, and regularly test the water in case harmful toxins have re-appeared. You should notice an immediate change to your fish’s health and wellbeing as soon as you improve the tank’s condition.

Improve Diet

Improving your angelfish’s diet with high-quality food provides them with the vitamins and minerals they need to stay healthy.

As we’ve already established, weakened immune systems are one of the leading causes of hole in the head disease, so focus on rebuilding your fish’s system with a healthy diet so that it can fight off diseases and infections before they develop and become a problem.

To speed up the process, you can also add a few drops of vitamins into the tank each day. This means that even if your angelfish don’t feel like eating, they’re still getting the nutrients they need.

You can also soak their pellets and flakes in vitamins before feeding. Any excess vitamins in the body will be excreted out of the system and won’t cause harm.

Remove Excess Fish

The only way to treat hole in the head disease caused by over-stocking is to remove excess fish into a separate tank. Use the water surface area rule, which we’ve covered, as a guide and work out how many fish your tank can safely allow. Allow for plants and other accessories in the aquarium.

While an air pump and air stone can help increase oxygen levels in the short-term, there’s only so much they can do. Not removing excess fish runs the risk of harmful levels of ammonia and nitrite from recurring, making fish susceptible to developing hole in the head disease for the second time.


Once hole in the head disease becomes advanced, the measures above aren’t enough to treat it. You’ll also need to use an effective medication, such as Metronidazole.

Metronidazole is an antibiotic that kills parasites in the intestinal tract, preventing hole in the head disease from getting worse.

A study published on Vin researched the effectiveness of standard hole in the head medications on angelfish and found that the Hexamita count dramatically reduced after administering a medicated feed treatment made with Metronidazole. It worked quickly within one day.

The study summarized that, as long as fish eat, the treatment should be effective. However, if the fish are anorexic, a bath treatment can be administered instead. While it took researchers 3 bath treatments to see the same results as the oral medication, no fatalities occurred.

Preventing hole in the head disease is the best way to ensure your angelfish never catches it. The condition is painful and deadly and usually becomes evident in the later stages, so it’s something all fish owners should try to avoid. When holes develop, it’s sometimes too late to save your fish as the parasite causes irreversible damage.

Regularly cleaning the tank and maintaining adequate hygiene levels is the easiest way to ensure your angelfish’s stress levels remain manageable.