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Discus Fish Diseases

Shocking Diseases That Can Take Your Discus Fish to Death's Door

If you are a discus fish hobbyist and have a whole lot of fish to care for, you need to know all about the discus fish diseases. The diseases mentioned in this article will tell you exactly what to look out for in your fish. Learn some discus fish care tips and medication as well, through this article.
Sayali Bedekar Patil
Last Updated: Feb 27, 2018
The discus fish are tropical fish that come from the Amazon. They are brilliantly colored, gloriously playful and beautiful to watch in your tropical aquariums. Yet, discus fish are fairly high maintenance, not only because they require temperature and water maintenance in their aquariums, but also because they can suffer from numerous fish diseases. Even if you are not actively breeding these fish, you still need to know about the diseases for the proper care of your pet fish. The diseases mentioned in this article are segregated into two divisions, namely, external diseases and the internal diseases. Let us have a look at them.
External Diseases
External discus fish problems are not at all hard to detect, if you regularly watch your fish, as they show clearly visible signs on the outside. If your fish is showing abnormal behavior or showing abnormalities in its coat color or texture, you need to research on this, real fast.
Toxic Aluminum
Discus fish require strict monitoring of the pH balance in your aquarium water. Any pH values above or below 8 and 5 respectively can be toxic for your dear fish. This is highly dangerous for your fish, as it actually hampers their breathing by interfering with their gill functioning. Aluminum ions clog the fish gills with a slimy layer, so keep an eye out for slimy materials around the gill area of your discus fish.
Fungal Infections
Your discus fish can easily fall victims to fungal infections, at localized sites on their bodies. Fungal spores found in water can easily attach to the bodies of your fish, especially if they are carrying wounds. These infections are also easily visible to the watchful discus keepers, as they appear as soft cottony or feathery attachments on the body of the fish. A fungal infection always comes secondary to either an injury or a parasitic break into the fish's skin. The worst part is that this infection can kill your fish. Regularly cleaning the water, giving salt baths to your fish (or adding salt into the aquarium) or using modern antifungals can surely help.
Parasitic Anchor Worms
Though rare infections to be seen in aquarium fish, you must still be aware of anchor worms infecting your discus fish. The visible signs of this parasitic infection are in the form of long, dark brown or red, thread like extensions hanging from your fish. If you see these, you know your fish has just encountered a worm attack. It is not just these parasites that one must worry about, but also the secondary infections that can occur due to the wounds left behind by them. Potassium permanganate dips, salt dips and modern antiparasitics are normally used to free the fish off this infection.
White Spot Infections
The 'ich' or the 'white spot disease' is a disease that is caused by a protozoan named ichthyophthirius multifiliis. This is a major tropical fish disease that troubles discus fish breeders to no end. Not only is this infection vastly contagious, but it is also known for its '100 percent mortality' rate if untreated in your aquarium. The signs of this fish disease range from white blister like spots on the skin and gills, decreased activity of the victim and pale and swollen gills. Your discus fish may suddenly lose appetite, show weakness and indulge in skin scraping when infected and unfortunately the infection spreads so fast that many times the fish do not survive the treatments.
Cloudy Eye Infection
There are many causes of cloudy eye disease, namely eye injuries, fungal infections, bacterial or parasitic attacks, etc. It is mostly seen in fish that are kept in water of poor quality. In cloudy eye disease, the eyes of the fish appear cloudy and unclear. This fish disease is treatable by changing water frequently, adding aquarium salt to your aquarium or adding chemicals like Acriflavine or Methylene blue to the tank when the infection is severe.
Columnaris Disease
The columnaris infection is a fish disease that can be identified by the white spots and scale margins on the skin of the fish. Quarantining an infected fish may be required in case of severe infection as the disease spreads fast, but it is not a dreaded disease that cannot be prevented or treated. Since it is caused by a bacterium, the standard measures to prevent it are to keep the water clean, keep the ammonia levels in check, stop overstocking the aquariums, keep temperatures moderate (high temperatures are perfect for bacteria multiplication) and keep a check on the pH balance and oxygen level of the water. Mistreating the disease is worse than the disease itself. So all discus fish hobbyists should first learn about it and then go about with its proper treatment.
There are many other external diseases like:
  • Fish and gill flukes
  • Fin and tail rots
  • Costia and chilodonella parasite infections
  • Aeromonas infections
  • Other fungal diseases
Many of the diseases mentioned here are not localized to the discus fish population and may affect other fish types as well. We will now have a look at the internal diseases.
Internal Diseases
The most important thing about the internal diseases is their proper and timely identification. The treatments and medications can only be effective if the diagnosis is a proper one.
Loss of Balance or Headstanding
If your discus fish is doing weird flip-flop antics in his tank, he may have an internal problem. Loss of balance can be caused by the poor water quality, digestive system blockages, swimbladder trouble, blood flagellates and even reactions to other medications. The treatment is simple, check all the parameters mentioned above. Epsom salts can relieve your fish of its boating while aquarium salt and antibiotics can help with the parasitic checks. Appropriate water changes should be made if water is the cause of the problem.
Fish Tuberculosis
Fish tuberculosis is a secondary disease that is caused by the tuberculosis mycobacteria that is found in the aquarium gravel, food remnants and other debris. Poor living conditions and overcrowding makes the discus fish susceptible to the attack of this deadly disease that can kill easily. Some symptoms of fish tuberculosis are bloating, emaciation, jerky movements while swimming and skin sores. One can see other symptoms like Popeye, loss of appetite and unusual spinal curvatures. Keep an eye out for this disease, if your fish is constantly loitering in one corner of the tank. When skin sores appear as torn out skin patches, treatment is difficult and so you must identify the disease and start the treatment long before this stage comes. Treatment of this fish disease must be done with care as this bacteria can easily infect humans through open cuts and wounds.
Dropsy and Popeye
Bloat, dropsy and popeye are very common internal discus fish problems. One can see the symptoms of these, when your fish is not eating properly, has a swollen abdomen, has bulging eyes or shows blisters. Bloats can be caused by overeating, intestinal parasites and internal bacteria infections. Epsom salts can be used to relieve bowel obstruction in your fish. Later stages of Popeye involve outward bulges of the eyes and spinal curving. Treatment is not always successful and so if your fish is showing any of the signs and is preferring to stay in one corner or at the back of his tank, diagnosis must be done immediately (and medications should be administered as early as possible).
This internal protozoan infection is not just a disease, but is known to affect other fish as well. Overcrowding of the fish tank, poor water conditions, nutritional deficiencies and stressful situations like bullying by other fish can make the fish susceptible to hexamitiasis infections. Whitish feces with slimy textures and unusual fish behavior like swimming backwards and hiding in the back, emaciation and loss of appetite are the early symptoms of this disease. Listlessness and lethargy, accompanied by the darkening of their bodies and eyes is shown in the later stages of the infection. Since it is a communicable disease, transmission to other fish can be avoided by quarantining the infected fish, for a while. Treatment is recommended in the form of the Metronidazole drug along with improving the other cause parameters mentioned above.
Tapeworm infections are also very common diseases in discus fish and are unfortunately fatal if not treated in time. Tapeworms are large worms that do not directly cause death of the fish, but weaken them for other parasitic attacks through the holes they leave behind. These worms can be seen attached to the skin of your fish and this is a very horrific, visible sign of a tapeworm infection. Tapeworm infections can be treated with the medication named 'Praziquantel', that tests have confirmed to be effective as well as safe. It is most effective when administered through the fish food, but can also be administered as a bath.
Head and Lateral Line Erosion (HLLE)
Also known as hole-in-the-head (HITH), this disease can be seen as skin de-pigmentation (loss of color) and the formation of small craters (holes) along the head and a lateral line on the body of the fish. As it is a chronic disease, it can be very problematic, even though it is not immediately fatal at the onset. This infection can make your fish anorexic and even leave them susceptible to other secondary bacterial and parasitic infections. Though there are many theories explaining the causes of this disease, it is the treatments that we are interested in. Cleaning the tank regularly, providing the fish with nutritious food and hexamita treatments like Metronidazole, work well to treat this infection.
Other internal diseases include:
  • Back area nerve damages
  • Emaciated discus and capillaria worms
  • Mycobacteriosis
  • Nematode infections
  • Vibrio infections
But don't worry, you will always have discus fish medications to rely on. Many common medication and fixes are available in the market that you can keep handy along with other fish supplies. However, you can prevent many of the diseases by keeping the aquarium water clean, providing fresh food to your fish and maintaining the right temperature.