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
Water Parameters
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
Discus Care 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. To replicate their natural habitat, the tank should include sand (sifters), driftwood (digestion/hiding), and leaf litter/blackwater.
This species should be kept in groups of at least 5 to reduce stress and encourage natural behaviour. Keepers should be aware that this species is not safe with ornamental shrimp, can be aggressive toward its own kind, and will defend a territory within the tank. 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.
Similar Species
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.
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.
Zebra Danio
Danio rerio
One of the most robust and active aquarium fish available. Native to South Asia, they are a model organism in science due to their genetics. They are extremely active top-level swimmers that must be kept in schools to prevent stress and fin-nipping. They prefer cooler, oxygen-rich water with a current.
German Blue Ram
Mikrogeophagus ramirezi
A strikingly colorful dwarf cichlid native to the Orinoco River basin. Famous for its vibrant blue spangles and peaceful demeanor compared to larger cichlids. They are strictly thermophilic (require high temperatures of 27-30°C / 81-86°F) and thrive in soft, acidic water. As 'earth-eaters' (Mikrogeophagus), they sift sand for food and form monogamous pairs.