10 Basic Things You Need to Know about the Discus Fish

We’re going to cover everything you need to know about the discus fish. This includes but is not limited to discus fish size, growth rate, lifespan, tank size, feeding, tankmates, overall behavior, aggression, breeding and egg laying.


Discus Fish

What Are Discus Fish?

Discus fish are a type of South American cichlid fish. They are freshwater fish. They are brighter than many other cichlids, and this explains why they’re often called pompadour fish. Their scientific name is Symphysodon discus.

There are several species and subspecies. These fish have been bred for bright and distinctive colors in captivity. You can find red, blue and orange variants. Their patterns may have brown, red, blue or green patterns. You can even find solid, red and orange variants; they’re bred for the same base color and stripe color. All of them share a laterally compressed body shape that gave them the “discus” name.

Red eyes are considered a desirable trait by aquarium owners, but this is a captive-bred mutation. Other fish will have yellow, grey or white eyes. Clean and bright eyes are an indication of health in the fish.

Development and Growth Rates

These fish are five to six inches or 12 to 15 centimeters in length. Males and females are similar in size and shape. Adults max out at 9 ounces or 250 grams of weight.

Life Span

Discus cichlids are sexually mature at about one year of age. They’ll reach their maximum size at two years of age. Like many other cichlids, they can live for ten years, maybe more.


These fish are very social and may school. This makes them unusual for cichlids. They actually do better in groups of eight to ten.

Feeding Behavior

These fish are omnivores. They’ll eat algae and plant material. They’ll eat detritus in the wild. They’ll eat invertebrates if they can get it. The myth that they’ll only eat red foods is false. You can feed them blood worms, bring shrimp, white worms, diced mussels or beef hearts. When giving them cut up beef heart, turn off the filters to minimize tank pollution. Then do tank maintenance. Remove all uneaten food.

Give them small amounts of protein before you give them fish flakes and pellets. In the wild, insect larvae may account for up to forty percent of their diet, but captive discus fish shouldn’t be given too many meaty foods.

Discus fish don’t tend to feed at the surface. You can solve this by giving them feeding cones of blood worms. Frozen blood worms are recommended, because live blood worms can carry parasites that make the fish sick. Freeze dried blood worms are even better.

General Care and Keeping In a Tank

You generally need to use a reverse osmosis filter to maintain the soft, slightly acidic water these fish live in. Tank bred fish are more likely to be able to survive in harder water; ask what conditions the fish are raised in to know exactly what conditions they need. Avoid getting fish from a variety of sources, because they may not be able to live in the same water conditions and may cross-contaminate with parasites and bacteria.

The best way to maintain the right water conditions is with a fully mature biological filter. Keep your hands out of the tank unless you’re wearing gloves. These fish are susceptible to bacterial infections.

These fish need very clean, slow moving water. Their ideal water temperature is 82 to 88 degrees Fahrenheit or 28 to 31 degrees Celsius. This is a higher water temperature than many other South American cichlids. The water hardness should between 1 and 8 dH. This replicates the soft water of the rivers these fish live in naturally. Their water pH should be between 6 and 7, while the ideal level is 6.5. If the water is too hard, add a piece of driftwood.

Discus fish are sensitive to ammonia in the water. This will cause them to lose their color and breathe heavily. If you see this, change their water immediately. Nitrate levels should be as low as possible. It needs to be below 20 parts per million. Remove decaying matter and add aquatic plants to control this. Discus fish require you to change at least 50 percent of the water every week to maintain ideal water conditions. Avoid rapid changes in water quality, since this stresses the fish. Don’t use chlorinated water in their tank.

Consider using a carbon-based filter to remove heavy meats and chloramines. A mature sponge filter may work, but a canister filter will be better, especially if you’re feeding them a lot of beef hearts.

These fish are ideal for planted aquariums. They want to live among the plant stems, and the plants help maintain the necessary water quality. These fish can live in a bare bottomed tank as long as the water quality is stable and perfect. When breeding a pair of discus, a bare bottomed tank is ideal since it creates a safe environment for the young.

Tank Size

These fish need a larger aquarium. Give each fish 20 liters of water. Give them at least three foot long aquariums with plenty of plants to swim among and at least a foot and a half of vertical space.

Tank Mates

Discus fish are social, an unusual trait among cichlids. Consider having several of them in the same tank. Do not put them in a tank with fish that nip other fish’s fins. Don’t put them in a tank with larger aggressive fish like Oscars. They can share a tank with similarly sized, social fish. They can share a tank with tetras.

The most important matter is whether the tank mates can live in the same water conditions as discus fish.
Don’t mix them with angel fish. The angels are so aggressive that it stresses the discus fish.

Breeding and Eggs Laying

These fish are difficult to breed in captivity. They need a deep tank and isolation from other adults. Water temperature needs to be above 82 degrees Fahrenheit, while pH should be 6.5 and remain there. The water should be soft, ideally 1 to 4 dH. While breeding, they need more protein. Give the fish a clay cone or pot so they have a hard surface to lay their eggs on.

Adults will care for their brood for the first four weeks. The adults will create a secretion through the skin that nourishes the fry. This secretion provides them with critical microorganisms and increases the survival rate of the young compared to broods fed brine shrimp and egg yolks.

Breeding pairs will separate from the school, because other cichlids may eat their young