Fish Diseases – Why Does Fish Have a Hole in the Head

Hey, dear friends. Have you ever found holes in your fish’s head? Sometimes, there may be holes in your fish’s head. Do you know what happened or why? It can be one kind of disease – the hole in the head disease. In today’s article, we will dive deep into this fish disease from its causes, prevention, and treatment. Let’s get started.

Content Table

Why does fish have a small hole in the front of its head?

A small hole in the head? It may be the result of erosion, which is also named “hole in the head disease”, “Hexamitiasisor”, or “lateral line erosion”. It is common in both freshwater and saltwater fish, such as goldfish, angelfish, betta fish, and cichlid fish. Generally, fish infected with the disease may just get a few holes in the head, or even many. Additionally, fish would lose their desire of eating and produce white and stringy feces.

In short, fish may show the following symptoms if they suffer hole in the head disease:

  • Holes in the head
  • Loss of appetite
  • Producing white and stringy feces
  • Fish become lethargic
  • Loss of color

Concerning the causes, here are two main reasons, including a parasite, and stress. Specifically, the parasite, called “Hexamita”, usually appears in fish’s intestines. And the parasites would thrive when fish are weak. However, fish may suffer death if the parasites grow in other internal organs. On the other side, stress may be the result of poor environmental conditions or behavioral factors. For instance, poor water quality, improper diet, limited space, injury from tank mate attacks, and so on. It would gradually decrease the immune function, and then bacteria on the fish skin would lead to localized infections.

Is the hole in the head contagious in fish?

The hole-in-the-head disease is contagious. Once one is infected, other fish may suffer. As a result, quarantine is essential. Besides that, you should observe your fish. However, can you prevent the hole in the fish head? Exactly, yes, you can do that. Just continue reading.

Maintain great water quality

Poor water quality would cause stress to fish. Hence, you should test the water and monitor the water parameters regularly, such as ammonia, nitrite, and nitrate levels, as well as water temperature. Likewise, doing water change is also critical. It is recommended to change 15-30 percent of water once a week. And an aquarium vacuum gravel can give you a hand. Vacuum gravel plays a role in water changing and aquarium cleaning. Exactly, it is a convenient aquarium gadget.

Besides, adding an aquarium filter would help you a lot. An aquarium filter can agitate and circulate the water. Also, water temperature fluctuation may cause stress on fish. Luckily, an aquarium heater helps maintain stable water temperature. Thus, you can add a heater to your fish tank.

Provide a proper diet

There are diverse food sources. But ideal food sources for varied fish species may be different. As a result, you’d better search before feeding. Moreover, a balanced and nutritious diet is equally important. It provides basic energy, vitamins, and nutrient substance for fish to survive.

Fish compatibility

Before setting up a new tank, you should consider the fish compatibility. Otherwise, they may fight with each other and then cause injury. It is not a good thing exactly. Furthermore, some fin nippers would nip fish fins. Also, some aggressive ones may bite other fish, and cause holes in the head. Consequently, choose proper tank mates for your fish. And you can get a peaceful fish tank.

Hole in the head treatment for fish

When facing the hole in the head disease, how to deal with it? You should clean the water exactly. Also, it is better to quarantine the fish, since the disease is contagious. Next in this part, we will cover more remedies.

Improve living environment

Facing holes in the fish’s head, you should check whether your fish tank is overstocked, lacks oxygen, or has poor water quality, and something like these. Then, check the water parameters with an aquarium water test strip. If they are not within the ideal range, you should adjust to improve the water quality. Usually, if your aquarium is at a low oxygen level, adding an aquarium air pump is advisable. An air pump makes sense in oxygenating the water and then improving the oxygen level. Accordingly, the stress could get reduced.

Apply medication

Metronidazole is feasible and effective. For fish being infected seriously, you should add the medication to the fish tank once each day, and last three days at least. In general, you should follow “250 mg of metronidazole for 10 gallons of water”. Furthermore, the medication may harm healthy fish. Consequently, it is recommended to remove the infected fish from another aquarium before applying medication.


Though there are cures for hole-in-the-head disease, it is best to prevent it. After all, fish suffering from the disease is not your wish, right? In a word, keeping appropriate daily maintenance could reduce the risk of getting sick or disease. And it can be a key point. That is all for today. More applicable therapies, welcome to share in the comment. We are happy to receive your sharing. Finally, thank you for your reading.

Leave a Comment

Your email address will not be published.