Hole in the Head

Hole in the Head Disease in Discus and Tropical Fish

Hole in the Head (HITH) in fish, also known as Head and Lateral Line Erosion (HLLE), is a very common aquarium and tropical fish disease that affects most Cichlids such as Symphysodon Discus, Oscars, and etc. Saltwater fish are also susceptible to head and lateral line erosion disease. The hole in the head disease usually starts with small holes in the the head and lateral line of the fish and as the condition progress you may notice some ugly pits, lesions, and wounds.

Hole in the head disease (HITH) also known as head and lateral line erosion (HLLE)

Is Hole in the Head Disease Fatal?

Although the hole in the head disease in the aquarium can be fatal to tropical fish such as discus, this is not always the case. If properly diagnosed and treated, especially those detected early, the hole in the head disease can be treated effectively by medication and proper diet.

Hole in the head disease in Discus Fish

Is Hole in the Head Disease Contagious?

Many people want to know how contagious the hole in the head disease is in discus fish and aquarium tanks? Even though head and lateral line erosion disease is not a 100% non-contagious/non-transmissible disease, it is not normally considered as a contagious sickness among discus fish and tropical aquarium environments. This is because there is a direct link between lateral line erosion disease (HLLE) and nutrition deficiency in fish.

Discus fish with lesions and wounds on head as a result of HLLE

What cause hole in the head disease in Fish

Nutritional factors and infectious disease contribute to HITH among discus and other freshwater tropical fish . Spironucleus is a flagellated protozoan parasite responsible for the disease hole in the head in tropical aquarium fish such as discus.  However,  many people believe that Hexamita can also cause the head and lateral line erosion disease in discus fish which is controversial. Although the hole in the head disease is caused by protozoan flagellates and needs be cured immediately by medication, you should also consider the other reason behind HITH which is nutritional deficiency. In fact, the lack of vitamins and minerals help disease development. A strong and healthy discus fish won’t get affected by protozoan Spironucleus and HLLE unless it is already suffering from nutritional deficiency and subsequent weakened immune system.

Here are some of the causes for the hole in the head disease:

  • Long-term use of activated carbon in discus tank.
  • Frequently feeding beef heart and frozen Bloodworms.
  • Vitamin deficiency and bad/poor diet.
  • Minerals and calcium deficiency.
  • Spironucleus flagellates.
  • Hexamita (Controversial)
  • High stress levels in discus fish. Stress can affect immune system of the discus.
Small holes on fish head
Discus fish with pits on head


Hole in the head is an easy disease to diagnose with some obvious medical symptoms including:

  • Small sores above the discus eyes and on the sides of the head.
  • Small pits around the head of the discus and/or it’s lateral line.
  • Small holes and lesions on the fish’s skin and around the lateral line which is the most common symptom of the hole in the head disease.
  • Stringy mucus on skin erosion and wounds.
  • Secondary infections and eventually death in discus fish.
White spots on head and lateral line as a result of erosion disease (HLLE)


As stated before, fortunately the hole in the head disease is not hard to treat at all. However, a quick and proper diagnosis is required to treat head and lateral line erosion disease effectively. So If you have discus fish, Oscar, or other Tropical Cichlid with holes, pits, and lesions around their head and face, just do not get scared and follow the instructions in this article. If the hole in the head disease diagnosed and treated in early stages of the progression, the fatality rate will be close to zero! However, this disease can develop rapidly over a period of days. The main priority is to control and eliminate the Pathogen that causes the hole in the head disease in your discus which is Spironucleus flagellate. For doing so, you should use medications that are effective in controlling protozoan parasites. Make sure to follow the directions and instructions from whatever medication that you use. Healing period must be completed fully, so don’t stop treatment once you no longer see the symptoms of the disease in discus, or even when the white holes are no longer visible on discus head. Here is a list of some of the well-known and effective medications and treatments to cure hole in the head disease or head and lateral line erosion in the aquarium fish.

HITH wounds and lesions can get affected by secondary infections


The best and most common treatment option for hole in the head disease in the aquarium environment, not only in discus but all other ornamental tropical fish is Metronidazole. 

API General Cure™ Powder

If you live in the United States, the API General Cure is and easy option to buy. You can find it at almost any local Petco or Petsmart stores. General Cure from API is a great medication to treat the hole in the head disease in discus and other tropical fish.

Fish Zole™

Fish Zole from Thomas Labs is a very water-soluble metronidazole -based medication that cure hole in the head disease effectively.

Hikari Metro+

Metro+ from Hikari is another effective product to treat HITH in discus.

Prevention Care

The hole in the head disease can easily be prevented in aquarium fish. A healthy diet rich in vitamins and minerals reduces the risk of HITH in fish. Even though it is not proven yet that there is a link between hole in the head disease development and activated carbon, there are some researches that show that it may increase the chance of development of the head and lateral line erosion disease in all tropical fish including discus by removing essential minerals from the water. So remove all activated carbons from the filtration system. Do not use pure R/O or distilled water. There are some necessary minerals and trace elements that are important to discus. As previously mentioned, one of the main reasons for this disease is lack of minerals in the water. Mixing distilled or reverse osmosis (R/O) water with tap water to add essential trace elements and minerals back into the purified water is not a bad idea. However, there are some aquarium commercial products to add minerals back into the aquarium water such as Sera Mineral Salt, Kent R/O Right Water, Seachem Replenish, and etc. Change your fish diet and bear in mind that too much beefheart with no additive can lead your discus to nutritional deficiency which make the fish prone to hole in the head disease. Discus must have a balanced diet including pellet foods, flake foods, vitamins, frozen foods, shrimp, and etc.

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