Why Are My Discus Dying? {Common Symptoms and Helpful Tips}

Are your Discus fish sinking? Are they breathing rapidly? Why are they dying? Let’s get right into it with this article to help your Discus Fish.

Why Are My Discus Dying? Discus fish require pristine water and are sensitive to spikes in ammonia. Overfeeding or lack of water changes can quickly lead to their death. Treating the tank itself with aquarium salt or medication can also be done with care and recommended dosages if you notice bacterial, fungal or parasitic infections.

Are Discus Fish Sensitive?

Discus Fish enjoy pristine water conditions. They do not take well to fluctuations in water chemistry that lead to sudden changes in pH, nitrates, ammonia and nitrites.

They benefit from more frequent water changes compared to most aquarium fish. The temperature should also be on the warmer end of their comfort zone. 82-89°F is suitable and comfortable.

Overeating can also lead to sensitivity with swim bladder issues due to bloating or constipation. Overeating can also lead to excess food waste, leftovers and debris which goes back to water conditions fluctuating and ammonia levels spiking.

Did I Overfeed My Discus Fish?

Looking at the tall and slender body of Discus fish, you wonder where all the food they eat goes. These fish love eating and are not picky, but they can overdo it.

Disease, illness, swim bladder issues and excess leftovers can lead to the sudden sinking or even worse, sudden death of your Discus fish. Feed smaller sized portions twice a day and remove leftovers or anything that is not eaten in 3-5 minutes.

A varied diet with liquid vitamin supplements or even beet juice works when you dip or soak their flakes, protein (brine shrimp, bloodworms) and fortify them with more nutrition to help your Discus fish recover or build stronger immune systems.

Why Are My Discus Fish Not Eating?

Bacterial, fungal and parasitic infections can lead to a Discus fish to stop eating. Check your water parameters right away and make sure you are performing water changes weekly or as often as daily during this time.

You may consider 1 tablespoon of aquarium salt per 5 gallons of tank water to treat any suspected parasites that may have entered the tank.

Aquariums must contain plenty of beneficial bacteria through a healthy nitrogen cycle to ward off illnesses as well. Make sure your Discus fish is eating plenty of protein rich food that doesn’t always float up top.

Discus fish like to rummage at the bottom of the tank. The substrate is preferably a thin layer of white, pool filter, silica based sand, to mimic their natural environment where they nibble bits on meaty foods and some plant matter as well.

YouTube video

Why Is My Discus Fish Breathing Rapidly?

Your Discus Fish that is struggling to breath or is breathing too fast may be a victim of nitrite or ammonia poisoning. Test the water first. An API Master Kit provides much better results than cheaper test strips.

Gill flukes can be killed with a parasitic wormer or other medications available for such a common illness at your local fish shop. Water changes from 35-60% should also be carried out.

Wipe down the sides of the aquarium. Add aquarium salt at 1 tablespoon per 5 gallons of water gradually. Look for clamped fins or scratching against surfaces. Check if the skin is red, blackening or peppered with white, gold or black spots.

How Do I Care For Discus Fish?

Discus Fish are generally hardy if you keep the water parameters ideal and place them in a 75 gallon tank or larger. The tank should be tall given the dimensions and taller appearance of your fish.

Follow the tips below to help care for your Discus Fish:

1.Water Parameters:

  • pH: 6.0-7.0
  • Temperature: 82-89°F
  • Water hardness: 18 ppm to 70 ppm
  • Chlorine: 0.001 ppm to 0.003 ppm
  • Ammonia: 0 ppm
  • Nitrite level: 0 ppm
  • Nitrate: less than 10 ppm

2. Keep the filter media and sponges full of healthy beneficial bacteria after your tank is cycled. Do not wash it out and risk losing or breaking your nitrogen cycle to protect your Discus fish from illnesses.

3. Check all your equipment including heaters, water pumps or filters for any cracks or leaking voltage that could lead to electrical charges in the water.

4. Perform regular water changes 1-4 times week up to 60% for Discus fish who demand pristine water.

5. Dechlorinate and use a conditioner in the tank. RO water also works well for encouraging pristine water.

6. Keep lighting on the dimmer side to avoid jumpy or skittish behavior. Turn off lights for 12 hours each night.

7. Test your water weekly.

8. Use aquarium salt at 1 tablespoon per 5 gallons of water in the main tank if you suspect parasites or bacterial infections.

What Are The Signs Of A Dying Discus Fish?

You may notice a Discus fish exhibiting the following behaviors or signs that indicate it could be sick or dying.

  • sinking to the bottom 
  • rapid breathing
  • not eating 
  • clamped fins
  • little movement
  • twitching tail fin
  • dark cheeks
  • skinnier than usual 
  • skin sores
  • tattered fins
  • fin rot
  • white spots 
  • fuzzy skin or mouth
  • cloudy or bulging eyes
  • rapid gill movement

Water changes, aquarium salt, medications and vitamin enriched meals with supplements like Selcon, liquid garlic and meaty foods are all encouraged in careful amounts.

Follow directions, doses, servings that are recommended for each course of action.

How Do You Treat Discus Disease?

Discus disease requires medication such as protozin, wormers, water changes and a full tank cleaning. You will have to wipe down the sides of tank and possibly reconfigure the entire aquarium.

Your surviving Discus fish could still pass this disease on to new tankmates. You may have to keep these fish who were previously infected on their own from now on.


Discus fish benefit from water changes, water conditioners, RO water, weekly water testing and tank cleaning more than most aquatic life. They can live for 10 years in captivity in large, spacious tank where the tankmates are just as peaceful as they are.

Your Discus fish can survive with medication, aquarium salt and supplementation when necessary and if the dosage or servings are kept within recommended amounts.

We hope your Discus fish recover or your future Discus fish do not succumb to the same fate as those we have cared for and lost in the past.


Thanks for visiting HelpUsFish.com and see you again soon for another article on Discus Fish or any aquatic life that you are interested. Bye or now!

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.