Common Discus Parasites/Bacterial Problems and Treatments:
Your discus will appear bloated as it swallowed a marble. There may be an indentation behind the bloated area as if pinched by your thumb and forefinger. Your discus may shimmy and shake or may not be able to maintain its balance and will generally look uncomfortable and be dark in color.
Cause: can be due to several things such as overeating, internal parasites, or internal bacterial infection.
Treat using Epsom Salt (Magnesium Sulfate), which is sold in most drug and grocery stores. Dosage for discus can be 1 to 2 teaspoons/10 gallons of aquarium water and if not better in 4 hours, you can add another dose not to exceed a rate of 1 to 2 tablespoons/10 gallons of aquarium water within a 24 hour period. This may relieve a bowel obstruction due to overeating. If discus is not better in 24 hours suspect a bacterial infection in the form of ulcers.
Epsom salt will not hurt your cycled filter or typical discus tank mates; however, it’s advisable to research your specific tank inhabitants and plants tolerance levels.
One or both eyes become cloudy.
Cause: can be due to injury to the eye, fungus, bacteria, parasites, but most often is due to poor water quality.
Treat initially providing clean water, water changes at 50%/day. Salt may be added at 1 to 2 tablespoons/10 gallons aquarium water. If the issue persists or becomes worse, Acriflavine or Methylene Blue sometimes helps. Remove carbon filtration during treatment.
Small crustaceans found in nearly every freshwater/saltwater habitat with thousands of various species. The parasitic carnivorous species most commonly attach to the discus gills, mouth, or skin causing erosion, ulcers, and or redness. Barely visible, they may be seen scrambling about in a jerky manner on the bottom of the tank and inside the filter.
Cause: Introduced by fish host or new plants.
Treat with “Fluke-Tabs” sold in online or in pet stores, which is also effective in the treatment for tapeworms, Anchor Worms, Body Flukes, Gill Flukes, Discus Lice, Capillaria and other Trematodes. First, be sure to clean the inside of tank and filters thoroughly followed by treatment with Fluke-Tabs. Day 1: do a 50% water change and dose one tab per 10 gallons. Day 2 & 3: do regular water changes. Day 4: Dose one tab/10 gallons. Remove carbon filtration during treatment. Please note that discus appetite may lessen for about a week following treatment.
Very little scientific evidence exists as to whether “Discus Plague” is a disease in itself or a combination of other known fish aliments. That said, your discus can turn dark in color appearing black, have clamped fins, remain inactive or group together at the top of your tank surface and/or point upward, you may see excess and/or shedding of mucus, body slime, may have fin rot, and most likely will lose their appetite. These multiple symptoms can appear quickly and fatality is common, so it is recommended to begin treatment as soon as possible.
Cause: is possibly due to the mixing discus from different sources, poor water quality, or your tank and filter(s) may have a very high organic load from decaying waste, food, and plant debris.
Treat by reducing tank temperature slowly to 82F, tank lights out and cover tank if needed to block room lighting, add extra aeration, and use Rid-Ich/Quick Cure for 48 hours for external parasites and/or bacterial issues. My personal preference is to perform a Potassium Permanganate bath over 4 hours in place of using Rid-Ich. Follow up with a 50% water change and add a double dose of Furan-2 over the next 24 hours only. Depending on the severity of issues, you may need to perform another PP bath in four days and repeat the above process.
Emaciated and De-worming
Your discus may eat well or even vigorously, but appear to be losing weight. More extreme cases discus can become razor thin more noticeably in the head area.
Cause: internal nematodes/worms.
Treat with a product indicating Fenbendazole as its active ingredient. Medicated flake is recommended and periodic preventative de-worming is advisable during your discus’s juvenile stage of development.
Fin and Tail Rot
Symptoms: may start with visible signs of that the fins/tail appears cloudy or opaque or the fins/tail appear to be rotting away.
Cause: by other discus nipping at fins/tail that becomes infected with bacteria or it can start from poor water quality.
Treat mild cases initially by improving water quality with a 50% water change. Salt may be added at 1 to 2 tablespoons/10 gallons aquarium water. If the issue persists or becomes worse, Acriflavine, Furan-2, or Bi-Furan can be helpful following the package instructions for dosage and duration. My preferred antibiotic is Furan-2, which is a good broad spectrum antibiotic containing Nitrofurazone & Furazolidone. Remove carbon filtration during treatment.
Skin or Gill Flukes/Subsequent Bacterial Issues
Small worm-like parasites up to 2mm in length. Technically, they are monogenean trematodes that are difficult to eliminate entirely. Initially, your discus may rub against tank objects or show signs of flashing and darting. They may breathe rapidly, gills may be flared, or they appear dark in color due to excess mucus and stay apart from the other discus. Flukes can cause lesions, reddening, and tissue damage as well as producing side effects such as hyperplasia of both skin and gill epithelium and create entry sites for secondary bacterial infections such. In more advanced cases, discus can show signs of being lethargic.
Cause: Introduced by a host and may remain in small quantities; however, resulting infestation in more than one discus is usually due to overcrowding, poor water quality, and water high in organic content.
Treat with Formalin (formaldehyde) sold in pet stores as Formalin and can be found in combination with dyes such in Rid-Ich and Quick Cure. One ml/10 gallons of water with a 50% water change after 8 hours. Do not raise temperature. Add extra air as it depletes oxygen. If you see an improvement after first dose you can treat every other day for two weeks. Dose the entire tank. Remove carbon filtration during treatment.
Products with formaldehyde as an active ingredient may impact your bio-filter depending on dosage and frequency of use. Products with Malachite Green require that your tank lights remain OFF during treatment.
Intestinal Flagellates (such as Heximita)
Your discus may quit eating or spit out its food. White, stringy, mucus-like feces will hang like a thread from the anus. Your discus may be dark in color and stay in the back (or pointed toward the back) of the tank away from the other discus.
Cause: is often is due to poor water quality.
Treat with products containing Metronidazole as its active ingredient such as Hex-A-Mit , Metrozol or sold as Metronidazole. It can be purchased online or at pet stores. Tank temperature should be gradually increased to 92 degrees for best results and dose daily 3-5 days after 50% water changes using 400-500 mg/10 gallons of water dissolved in warm non-chlorinated water. Keep water temperature elevated for a week after treatment ends. It may take a week or so for the discus to regain its normal appetite. In severe cases, you may need to dose every 8 hours for three days. You may dose all discus in your tank or remove affected discus to a hospital tank. Will not affect your bio-filter. Remove carbon filtration during treatment.
Hole-in-the-Head (HITH) Disease
Small grey pin-like holes that appear and can develop into larger craters on the head, around the eyes, and along the lateral line. Left untreated, secondary infections may develop and become life threatening.
Cause: is widely debated, but it is believed that it can be due a deficiency in the immune system, water quality and/or nutrition, or possibly a protozoan called Heximita, or even the use of activated charcoal used for chemical filtration. Little scientific research has been done to substantiate the possible causes.
Prevention/Treatment: by increasing the number of water changes and tank and equipment cleaning to improve water quality, regulate a varied diet enriched with vitamins; especially, A, C & D. Due to the association with Heximita, the preferred medicines contain Metronidazole as its active ingredient or it can be purchased alone. If our discus is eating, it’s best to use medicated food and increase the tank temperature to 92F for best results. Granule form dissolved in warm non-chlorinated water will be absorbed through the gills and skin. Dosage and duration should be as above in the treatment of Heximita.
White dots that are flat non-parasitic flat worms that most visibly appear on any smooth surface such as your tank walls and inside the filter. Planaria are not harmful to your discus.
Cause: is most likely due to overfeeding or accumulation of uneaten foods in/on substrate or filter area.
Treat by decreasing the amount of food fed and use a pre-filter if food and feces are being sucked into the filter and periodically rinse on a regular basis in non-chlorinated or old tank water during water changes. Initially, clean your tank. Vacuum your substrate (if applicable), rinsing filter(s), wiping down the inside glass/acrylic walls and increase your water changes. Be sure to wipe down these areas regularly.
Once infested, it can be difficult to get rid of Planaria with just water changes, a reduction in food quantity, or cleaning up uneaten food. If the issue persists, you may want to consider the use of Formaldehyde and Malachite Green (F&MG) using products such as Rid-Ich/Quick Cure dosing at 1ml/10 gallons or consider using potassium permanganate (PP) to disinfect your tank. PP should be used with extreme caution.
IMPORTANT: Regarding the use of medications, salt etc., more does not mean better! Do not over dose without having the expressed instructions of a more experienced hobbyist, breeder, or professional. If possible, it is highly recommended that you provide those assisting you pictures to aid in the proper diagnosis and development of a treatment plan, which should include documenting any unusual changes in behavior and/or environment such as new fish, foods, plants, routine, water test parameters etc.
Hospital/Quarantine Tanks – are advisable in the treatment of fish illness and parasites in isolated situations rather than treating in their home tank. The main reason is to prevent the spreading illness or parasites.
Tank size should be proportionate to your needs given the typical adult size of your fish, but in general a 10, 20, or 30 gallon tank should be sufficient. Additionally, the use of a smaller hospital tank such as these will limit the amount of meds needed, which will be less costly in the long term.
Filtration can be at a minimum using an inexpensive sponge filter(s) to provide plenty of biological filtration as well as aeration given mechanical charcoal cartridges are typically not used at this time and some medicines require NO lights that will render the medicine ineffective such as with the use of Quick Cure or Rid-Ich and other products that contain Malachite Green.
Oxygen, in my experience should be increased by adding an extra bubble wand or air stone to aid in the healing process as well as when due to certain medications may deplete the oxygen more than others.
Temperature as an aid to treatment should be adjusted slowly as needed depending on the aliment and medication being used. In general, temperature should be decreased during bacterial treatments given higher temperatures can enable the production of bacteria and increased when using parasitic treatments given some parasites can not readily tolerate higher temps. That said, higher heat reduces the oxygen content; therefore, it’s important increase oxygenation with by adding a bubble wand or air stone.
Antibiotics - Use of these specific medications referred to above with discus can result in a build up and resistance to these medications over time depending on frequency of usage; therefore, it is recommended that you consult with a more experience hobbyist, breeder, or professional for current recommended products.
Medication compatibility – some medications and treatments can be used in conjunction or in tandem depending on the severity and or proper diagnosis of multiple issues. Diagnosis can be difficult and some symptoms can be shared or appear as a secondary issue to the primary problem. Be sure to do your research and consult with a more experienced hobbyist, breeder, or professional to provide the best plan for treatment with recommended medications and proper dosages.
Medication Form – Many of the recommended medications above are readily available in the form of granules/powder, liquid, or medicated flake. Generally speaking, medications are more effective when ingested; therefore, flake or mixed with food is preferred when your discus is still eating. If not, powders and liquid forms can be pre-mixed with non-chlorinated water and added to your tank following the manufacturer’s instructions and absorbed through the skin and gills.
Medication Life Span – varies depending on dosage. In general, most medication’s effectiveness dissipates within 8-24 hours with insufficient residual potency after that time. Follow the manufacturer’s dosage instructions and note when water changes are needed or research for possible interactions when switching to another medication within close proximity.
PS: I hope to update this as needed. If you have any recommendations, feel free to PM me.
I'm not always logged in, but if you PM me, I'll get back to you quickly.
This thread has probably eliminated 100+ future threads with people asking about their discus's illness lol.
Not really. Seems the stickies are the last thing they read. But we will sure lead them to this thread often in the future. Another good write up.
Right, well it was a good write-up anyway!
Thanks Crispy and Dom!
I'm not really one to write articles per se when footnotes and references are standard. Nor is this information specific to any one source or original. It's simply something I compiled as a quick reference. That said, I thought I would share it here to help support other hobbyiest like me on AC that may have health issues in their tanks from time-to-time.
My cumulative knowledge is credited to many fine hobbyiest similar to me willing to share and pass it along. I would also like to recommend the following books:
Discus Health by Utergasser
Fish Disease, Diagnosis and Treatment by Noga
The Naked Truth by Andew Soh
Discus Problems and Solutions by Andrew Soh
I'm not always logged in, but if you PM me, I'll get back to you quickly.