Why is my Discus not Eating?

It’s okay for a discus to lose its appetite for a few days. But if this behaviour prolongs, then it may be a cause for concern.

Why is my Discus fish not eating? It might be stressed due to changed or improper tank environment. Discus fish can also be stressed and stop eating due to prior mishandling. Illness is a leading cause behind loss of appetite for discus fish.

To avoid any unfortunate outcomes, it is essential to figure out your Discus’ issue, that too immediately, or it can quickly become too late.

Why won’t my new Discus eat? (Video)

Sickness in discus fish

If your discus has been refusing food for more than a week now, then chances are that it has developed a disease.
To identify any signs of sickness other than loss of appetite, you must carefully observe your Discus fish.

External Diseases will have clearly visible signs on the body of your discus. Amongst them, Ich is the only disease in which loss of appetite is a primary symptom.

White Spot Infection/ Ich

It is a common tropical fish disease caused by a protozoan named Ichthyophthirius multifiliis. This infection is not just vastly contagious, but can also cause the death of your fish, if left untreated. The disease spreads really fast. Its signs range from white blister-like spots on skin & gills, decreased activity of the victim along with pale and swollen gills. Your discus fish may suddenly lose appetite, show weakness, and indulge in skin scraping when infected.

It can be treated naturally by changing temperature or adding aquarium salt. In severe cases, medication becomes necessary for the fish.

However, internal diseases will demand a more careful inspection of your fish’s body and behaviour.

Dropsy and Popeye

Bloat, dropsy, and Popeye are very common internal discus fish problems. One can see the symptoms of these illnesses when one’s fish is not eating properly, has a swollen abdomen, has bulging eyes or blisters.

Epsom salts can be used to relieve bowel obstruction in your fish. If your fish is in the later stages of Popeye, you will observe outward bulging of eyes and spinal curving. Under such circumstances, medications should be administered as soon as possible after consulting an expert.


This internal protozoan infection is a communicable disease. The infected fish can be quarantined for a while, to avoid transmission. It can be caused by overcrowding of the fish tank, poor water conditions, nutritional deficiencies and stressful situations like bullying by other fish.

Whitish faeces with slimy textures and unusual fish behaviour like swimming backwards and hiding in the back, emaciation and loss of appetite are the early symptoms of this disease. It might as well make your discus lethargic and appear darker. This disease can be treated by improving water parameters or by Metronidazole drug. Beware to only administer any type of medication after consulting an expert.

Fish Tuberculosis

Fish tuberculosis is caused by the tuberculosis mycobacteria that is found in the aquarium gravel, food remnants, and other debris.

Some symptoms of fish tuberculosis are bloating, emaciation, jerky movements while swimming and skin sores.

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Fish tuberculosis and Popeye have a few common symptoms like loss of appetite and unusual spinal curvatures.

Once the skin sores appear as if they are torn-out skin patches, the treatment becomes extremely difficult.

Therefore, 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.

Prevention is always better than cure. It is highly important to take preventative measures before the disease begins to manifest in your fish. If you keep your fish happy, healthy and well-fed, this will boost its immune system. Wounded or otherwise weakened fish should be moved to quarantine tanks and given time to recuperate. Otherwise, they may serve as breeding grounds for micro-organisms in the main tank.

New Discus

Generally when discus fish are introduced to a new environment, they get stressed. The time they take to adjust to the new surroundings ranges from a couple of days to about two weeks. During this adjustment-period, they may refuse to eat almost anything.

So, if you’ve recently brought your Discus home or changed it’s tank, and everything else appears to be fine with it physically, then you need not worry. It’s absolutely normal for them to avoid food for some time after changing tanks.

However, there are a few measures that should be taken before a new fish is allowed into the community aquarium.

Plants, substrate, equipment etc should be sterilized to kill any potentially harmful bacteria. If the tank isn’t new and previously had sick fish in it, it should be cleaned out with bleach and left to dry before you restock it.

Feeding Details

If your Discus is taking too long to settle in, and has not eaten a single thing for an alarmingly long time period, then it’s time for you to change its feed.

Discus fish can literally feed on anything they lay their fins on. Be it fish flakes, pellets, frozen or even live food.

Naturally they prefer live foods, such as bloodworms, black worms, and even white worms. Not only are these foods easily acquired and prepared, but they also happen to be one of the best foods for discus fish in terms of nutritional content. For vitamins and minerals, you can provide them with brine shrimps.

Dry foods such as fish flakes and fish pellets can also be given to them. Though this type of food does provide essential nutrients, but it must be supplemented with live food to attain optimum health for your discus fish. To avoid bloating, soak the fish pellets before feeding.

Young discus require constant feeding. Baby discus fish will eat 10 to 12 times per day while the slightly older ones will eat up to 5 times per day. The adult discus fish need to be fed 2-3 times per day; although they live as long as 1-2 months without eating, if necessary! Discus fish like being fed in the middle of the tank. You should be careful not to overfeed them and drop in enough food which can be consumed within 5 minutes by the fish.

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Sometimes your Discus fish might not eat its food immediately. As a result, the food will sink to the bottom of the aquarium. If that food is not removed within 2 days, it will start to rot leading to growth of harmful bacteria. To avoid this, include a bottom feeder in the fish tank or clean the leftover food manually.

Also, to persuade your fish to take any new food, you might use of garlic as many discus owners have found it to be helpful for introducing new diet.

Tank Requirements

Coming from the Amazon, discus require a fairly high maintenance which include water, temperature, pH, and tank size requirements.

The tank you keep your Discus in should at least have a water capacity of 200 litres (52.83 gallons) or more. A tank smaller than that might stress out the fish which grow up to be 20-25 cm long (8-10 inches).

Appropriate temperature and pH for discus fish are 28-32° C (82.4-89.6 degrees Fahrenheit) and 6.0-7.0 respectively. Water changes should be conducted regularly; 25% water should be changed weekly.

Even though Discus belongs to the cichlid family, it has a peaceful nature. It is a schooling fish, so it prefers to stay in groups of 5- 6 species at least and it hardly stands being alone.

Neon tetras, the ram cichlid, clown loach, rummy nose tetra, Congo tetra, cardinal tetra and different types of catfish are highly  compatible with the Discus fish and make good tank-mates for them.


Why is my Discus Aggressive? Being Cichlids, discus fish have a certain degree of aggression in them naturally.

And the fights amongst them are normal to some extent. It helps to strengthen the pair bond. Pairs of fish that are not properly matched (i.e., which are not equally aggressive or submissive) need to be re-paired.

This aggression, however, may increase if the water parameters are imbalanced. Inappropriate tank mates can also give rise to territorial aggression in this tropical fish, which can not only lead to fights but can also deteriorate their health. Discus can also become aggressive if not kept in schools of at least 5-6 fish.

What to feed breeding discus? Breeding Discus should be fed with protein-rich foods. Diversifying food sources will help to balance the Discus’ diet. Professional breeders use beef heart but this should also be combined with bloodworms and vegetable matter such as spinach to aid in vitamin uptake. To maintain good health, use some high-grade tropical granules twice a week to supply them with the required nutrients and vitamins that they may be lacking.

Should I use tap water or reverse osmosis water for my discus? Generally, fish will adapt to their water type over time. But if you still wish to provide them with the best of conditions, then it is better to keep them in a mixture of both tap water and Reverse Osmosis (RO) water. The treated tap water should be 20% in ratio while the Reverse Osmosis water should be 80%. Any amount of acid or base added to RO water can cause huge fluctuations. This can be a bit difficult to handle, therefore, a mixture of RO and tap water is more preferable.

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Nadine Oraby

My name is Nadine; I am a passionate writer and a pet lover. People usually call me by the nickname “Joy” because they think that I am a positive and joyful person who is a child at heart. My love for animals triggered me to create this blog. Articles are written by vets, pet experts, and me. Thanks for visiting. Your friend, Nadine!

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