Known as the 'King of the Aquarium', Discus are stunning, heavily laterally-compressed cichlids. They are famous for their demanding husbandry, requiring high temperatures (28-32°C / 82-90°F), pristine water quality, and specialized diets. They are schooling fish that establish a strict pecking order and must be kept in groups to prevent intense bullying of a single weaker fish.
At a Glance
Tank Requirements
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Water Parameters
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Temperament & Compatibility
Available Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Adult (Standard)
Fully grown adult Discus. The bioload modifier is set to 1.5 because, while compressed, they are extremely tall and thick for their shape category. They are generally peaceful with appropriate warm-water dither fish (like Sterbai Corydoras or Cardinal Tetras) but aggressively enforce hierarchy among themselves.
Same care requirements as the base species
Also known as: Pigeon Blood, Blue Turquoise, Marlboro Red, Cobalt, Leopard, Adult Discus
Juvenile (Grow-out)
Juvenile Discus require massive amounts of high-protein food (like beef heart) fed multiple times a day to avoid stunting. This frequent feeding requires intense filtration and extreme water change schedules. Can be temporarily housed in smaller grow-out tanks.
Differs in 4 traits from base species
Also known as: Baby Discus, 2 inch Discus, Juvenile
Top Tank Mates
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🟢Ideal Tank MatesDiscus Care Guide Summary
The Discus, scientifically known as Symphysodon aequifasciatus, belongs to the Cichlids - South American family group. Adults reach a maximum size of approximately 18 cm and have a compressed body shape with a moderate growth rate. Classified as mostly peaceful, this species primarily occupies the mid-level and bottom zones of the aquarium and produces a high level of biological waste.
To thrive, the Discus requires a freshwater only aquarium with a minimum volume of 250 litres and a tank length of at least 120 cm. Water temperature should be maintained between 28°C and 32°C, with a pH range of 5–7.5 and a general hardness of 1–12 dGH. A low water flow is preferred. An aquarium test kit can help you monitor these values.
Due to its specialist needs, the Discus is best suited for fishkeepers who can provide a carefully planned setup. This species is available in 2 varieties: Adult (Standard) and Juvenile (Grow-out). Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Discus Habitat Setup
When setting up an aquarium for the Discus, a low water flow best suits their natural preferences. Because this species occupies the mid-level and bottom zones, the aquarium layout should prioritise open swimming space in the centre of the tank for free movement and sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include a sand substrate to accommodate their sifting behaviour, driftwood, which can serve as both a hiding place and a dietary supplement, and leaf litter or blackwater tannins to replicate their natural soft-water habitat. Browse aquarium sand substrate options to find the best fit.
Discus Compatibility Notes
Classified as mostly peaceful, the Discus is a social species that requires the company of its own kind to thrive. When choosing tankmates, ornamental shrimp are not safe companions, conspecific aggression can be intense, especially in smaller tanks, territorial behaviour may cause issues if hiding spots or floor space are limited, and boisterous or fast-moving tankmates may cause this species undue stress. Selecting tankmates that favour different water layers from the mid-level and bottom zones can help reduce competition and territorial overlap.
Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Discus.
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
180 Gallon Standard
350 Liter (120cm Deep)
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Frequently Asked Questions About Discus
How big does Discus get?
Discus (Symphysodon aequifasciatus) typically reaches a maximum adult size of approximately 18 cm. They have a compressed body shape and a moderate growth rate.
What tank size does Discus need?
A minimum aquarium volume of 250 litres and a tank length of at least 120 cm are recommended for Discus. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Discus need?
Discus thrives in freshwater only conditions with a temperature range of 28–32°C, a pH between 5 and 7.5, and a general hardness of 1–12 dGH. A low water flow is preferred.
Is Discus peaceful or aggressive?
Discus is classified as mostly peaceful with an aggression score of 4 out of 10. They are generally well-suited to peaceful community tanks.
Can Discus live alone?
No, Discus should be kept in groups of at least 5 to reduce stress and encourage natural behaviour.
Is Discus safe with shrimp?
No. Discus is known to eat ornamental shrimp and is not recommended for shrimp tanks. Even larger shrimp species like Amano Shrimp may be at risk.
Does Discus have any special tank requirements?
Yes. Discus benefits from sand (sifters), driftwood (digestion/hiding), and leaf litter/blackwater in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Similar Species
Uaru
Uaru amphiacanthoides
A large, relatively peaceful but highly gregarious South American cichlid. Often kept with Discus due to their shared need for very warm, pristine, acidic water. They are notorious herbivores that will devour almost any aquatic plant, and they actually require grazing on driftwood for proper digestion. They must be kept in groups.
Betta (Siamese Fighting Fish)
Betta splendens
The Siamese Fighting Fish is an aquarium icon known for its labyrinth organ (allowing air breathing) and vivid colors. While hardy, they require heated, filtered water (24-30°C). Males are solitary and fiercely territorial. Females are generally less ornate but can be kept in 'sororities' with strict precautions (minimum 5 females in 75L+).
Sterba's Corydoras
Corydoras sterbai
A highly popular and peaceful schooling catfish known for its striking white-on-black spotted pattern and bright orange pectoral fins. Uniquely among Corydoras, they thrive in higher temperatures, making them excellent bottom-dwelling companions for warm-water species like Discus. They are obligate shoalers and must be kept on fine sand to prevent the erosion and infection of their delicate barbels.
White Cloud Mountain Minnow
Tanichthys albonubes
A hardy, peaceful, and active schooling fish famous for its ability to thrive in unheated, sub-tropical aquariums. Native to the mountain streams of China, they feature a bronze body with a striking neon-like lateral stripe and red-tipped fins. They are strictly schooling fish and must be kept in groups to feel secure and display their best colors.
Guppy
Poecilia reticulata
One of the most iconic and widely kept aquarium fish. Renowned for their incredible colors, hardiness, and prolific breeding. As livebearers, they give birth to fully formed, free-swimming fry. Males constantly pursue females for mating; therefore, a ratio of at least 2 females per male is strongly recommended to disperse stress.
Oscar
Astronotus ocellatus
A highly intelligent, large, and personable South American cichlid often described as a 'water dog'. They are notoriously messy eaters, heavy waste producers, and will enthusiastically rearrange tank decor and uproot plants. Any fish small enough to fit in their mouth will be eaten. They require excellent filtration and strict water maintenance.