Hole In The Head Disease in Oscar Fish (Causes, Symptoms and Treatments)

Hole In The Head Disease in Oscar Fish

AquariumFishCity.com is supported by our readers. When you buy through links on our site, we may earn a commission.

Also known as the Velvet Cichlid or Tiger Oscar, the Oscar fish is a species of the Cichlid family that originated in the Amazon basin. 

Commonly found in South American markets, Oscars are labeled as non-native pet species in the United States. Typically found in green to dark brown colors, these fish are great ornamental species to have in your aquarium.

However, it is worth noting that this species is a little aggressive and needs special care. This includes being watchful of the hole in the head disease in Oscar since they are very susceptible to Hexamita infection. 

Want to know more about this disease? Keep reading then!

Causes Of Hole In The Head Disease In Oscar Fish

The root cause of the disease is yet to be pinned down, but there are several causative factors responsible for the infestation. 

Fish sense their surroundings using a cluster of sensory cells called neuromasts, which are mainly located near their head and lateral line holes. These receptive structures are prone to bacterial, protozoal, fungal, and chemical attacks. 

The symptoms don’t really occur in the presence of one causative factor and are observed only when there are two or more contributors. That said, some of the common causes of hole in the head disease in Oscar are:

Hexamita Infection

Do you know about this vile flagellate parasite? You might have heard about Hexamita in reference to intestinal tract infections. The infection isn’t just limited to humans or animals but extends to the aquatic kingdom as well. 

The protozoan initially infects the intestine and then slowly stems over the kidneys, abdominal cavity, gallbladder, and spleen. When the infection has spread sufficiently, the classic white lesions associated with the hole in the head disease start appearing.

You must have guessed by now; by the time these spots appear, the matter goes well out of hand. What makes it worse is that these lesions open up and ooze out tiny white threads containing protozoan larvae. 

It’s so uncomfortable even to read, right? Imagine your fishy going through all this. We also find it imperative to mention that these holes become susceptible to secondary fungal or bacterial infections and may lead to death in severe cases.

Therefore, you must start clinically treating your Oscar fish at first sight of this disease. 

Nutritional Imbalance In The Tank

The occurrence of the disease is also linked with vitamin or mineral imbalance in their habitat. Many aquarists have linked the frequent instances of disease with the increased biofiltration and overexploitation of carbon filters.

It is speculated that the filters remove integral elements from the water, which leads to the hole in the head disease. However, some people also argue that this imbalance of nutrients is an “effect” rather than a “cause” of the disease. 

Due to the presence of Hexamita in the intestine, fish stop taking in necessary minerals from water and start malabsorption. You can read the situation from both points of view.

Stressful Environment

The HIIH disease is also likely to occur if Oscars stay under high stress for a prolonged period. Stressful conditions weaken the immune system in fish and make them prone to several disorders.

Improper nutrition, unclean surroundings, overcrowding in the tank, and poor water quality are common stress inducers and can cause health problems. You must take care of these parameters, especially if you have old fish in your aquarium.

Signs Of Oscar Fish Hole In The Head

The most obvious sign of the syndrome is the characteristic white pitting-type lesions that occur on the head and body’s lateral lines. Now, the openings might not be obvious at first, but if you don’t initiate treatment or changes in the water, the situation is bound to get worse. The holes will enlarge and develop several other infections. 

Since Hexamita primarily affects the intestine, the initial signs of the disease can be observed by keeping a close eye on your fish’s eating habits. If your Oscar is experiencing a loss of appetite, it might be one of the first symptoms of the disorder. But this isn’t a conclusive sign as several reasons may cause appetite loss. 

The most reliable way to diagnose the disease is by identifying the white lesions during the early stages. 

Oscar Fish Hole In The Head Disease Treatment

We’ve been talking about the cause and the effects of the disease all this while. Now, let’s discuss how to cure it. 

Since the disease is induced by so many factors, the approach to curing it should be multi-faceted. If we map out, there are three main objectives that’ll help us get rid of the infection: 

  • Remove Hexamita from fish’s intestine
  • Improve the quality of water
  • Improve the minerals and nutrients in the water

The parasite can be treated by adding the antibiotic metronidazole to the tank water. It works wonders for treating bacterial and fungal infections. Along with that, you can add Kanacyn, Maracyn, and Furan. 

Closely observe the water quality of your aquarium and routinely adjust it as per the standards suggested for your species. You can improve the nutritional quality of your tank by adding lightly steamed broccoli or seaweed strips to the water. Following all these steps will help in the swift recovery of your Oscars. 

Final Thoughts 

Oscars are beautiful ornamental fish that can be slightly invasive in aquariums and require a lot of maintenance and care. If you have them in your tank, you know how notorious they can be at times. But regardless of that, they are adorable little creatures.

The species is prone to catch the hole in the head disease if not looked after well, so you need to be watchful for that. Even if your fish ever gets infected, you know how to treat it now!

Was this article helpful?
Jeff Colt

Jeff Colt

Hello, I'm Jeff- an aquarium enthusiast with over 25 years of experience caring for a wide array of tropical fish, including koi, goldfish bettas, cichlids and more! For me: Aquariums are like jello - there's always room for more!

Leave a Comment