How big does Discus get?

Discus reaches an adult standard length of 15–20 cm (excluding the caudal fin). Size the tank for that, not for the juvenile you bring home — the difference is often several times over, and upgrading later costs more than buying once.

What water does Discus need?

27–31 °C, pH 5.5–7, 1–8 dGH, 0–4 dKH. That is only 4 °C wide, so stability matters more than hitting a particular number.

What is the smallest tank for Discus?

At least 200 L, and no shorter than 90 cm. That is the floor for long-term keeping, not for short-term survival: volume buys water stability and length buys swimming room, and neither substitutes for the other. It is a schooling fish: keep at least 5 together. Fewer than that and it hides, loses colour, and aggression has nowhere to spread.

What is Discus like to keep?

Temperament: peaceful. Difficulty: advanced. It occupies the middle and is omnivore. With plants it is "Leaves plants alone".

Can Discus be kept with its most common tank mate?

The checker returns "Keep with care". The shared temperature window is only 27–28 °C (1 °C wide). A heater fault or a summer heatwave will push the tank past one side's limit — run a separate thermostat as a backup.

G-01 / 21Freshwater

Discus七彩神仙

Symphysodon aequifasciatus · Cichlidae

A large cichlid demanding 27-31 °C soft water and daily water changes: not a beginner fish.

Illustration to come

G-01 / 21 · Discus Symphysodon aequifasciatus

SpecificationsFish atlas

Name: 七彩神仙
Scientific name: Symphysodon aequifasciatus
Family: Cichlidae
Origin: Amazon basin, South America (Brazil, Peru)
Adult size: 15–20 cm
Temperament: Peaceful
Diet: Omnivore
Water level: Middle
Level: Advanced
School size: ≥ 5
Min. tank: 200 L
Min. length: 90 cm
Plant safe: Leaves plants alone

Water requirementsFreshwater

Temp.27–31 °C

pH5.5–7

Hardness1–8 dGH

Alkalinity0–4 dKH

Units: temperature in °C, hardness in German degrees (dGH / dKH), marine salinity as specific gravity at 25 °C, volume in litres. These are the values recorded for the species and do not follow the site unit switcher.

Keeping notes

1Requires 27-31 °C, a band that does not overlap the needs of most tetras and corydoras.
2Daily 20-30 % water changes keep adults in shape and eating, and ammonia must stay at zero.
3Keep five or more; in groups under four the weakest fish stops eating.
4Feed beefheart mix, frozen bloodworm and granules in small frequent meals, removing leftovers at once.
5Cardinal tetras and Sterbai corydoras take the same warm soft water and make the best tankmates.

Check a tank mate

Jump straight to the verdict for Discus against this one — no need to pick it again.

Frequently asked questions

How big does Discus get?: Discus reaches an adult standard length of 15–20 cm (excluding the caudal fin). Size the tank for that, not for the juvenile you bring home — the difference is often several times over, and upgrading later costs more than buying once.
What water does Discus need?: 27–31 °C, pH 5.5–7, 1–8 dGH, 0–4 dKH. That is only 4 °C wide, so stability matters more than hitting a particular number.
What is the smallest tank for Discus?: At least 200 L, and no shorter than 90 cm. That is the floor for long-term keeping, not for short-term survival: volume buys water stability and length buys swimming room, and neither substitutes for the other. It is a schooling fish: keep at least 5 together. Fewer than that and it hides, loses colour, and aggression has nowhere to spread.
What is Discus like to keep?: Temperament: peaceful. Difficulty: advanced. It occupies the middle and is omnivore. With plants it is "Leaves plants alone".
Can Discus be kept with its most common tank mate?: The checker returns "Keep with care". The shared temperature window is only 27–28 °C (1 °C wide). A heater fault or a summer heatwave will push the tank past one side's limit — run a separate thermostat as a backup.