AquariumSetup

cichlid · freshwater

Discus: adult size, tank size & tankmates

The Discus (Symphysodon spp.) grows to about 6.6 in (14 cm SL). It needs a tank at least 47 inches long and about 67 gallons. Keep at least 6 together, at 79–86°F.

Try it in the tank builderSee tankmates

How big it really gets

Drawn to scale against common tank lengths. Green bars meet the minimum tank length from our sources.

Adult: about 6.6 in · needs 47 in of tank10 gal · 20 in ✕20 long / 29 · 30 in ✕40 breeder · 36 in ✕55 / 75 gal · 48 in ✓125 gal · 72 in ✓
Needs special care. Sold into ordinary community tanks, but needs warmer (79-86 F), softer water than typical community fish.

Will it fit your tank?

Check a full stocking list →

Quick facts

Adult size
6.6 in (14 cm SL)
Minimum tank
47 inches long and about 67 gallons
Temperature
79–86°F
pH
5–7
Hardness
0–5 dGH
Group size
6+
With other fish
peaceful
With its own kind
semi-aggressive
Swims
middle of the tank
Diet
carnivore
Care level
advanced
Lifespan
not stated in sources

Watch for: may eat baby shrimp

Discus tankmates

Checked with the same rules as our tank builder: temperature overlap, pH and hardness, predation and mouth size, fin-nipping and temperament. Tank size is left out here; check it in the builder.

Good tankmates

Use caution

Avoid

All 105 species we checked against the Discus
SpeciesVerdictWhy
AngelfishCompatibleNo conflicts found
Bala SharkCompatibleNo conflicts found
BettaCompatibleNo conflicts found
Black Neon TetraCompatibleNo conflicts found
Bleeding Heart TetraCompatibleNo conflicts found
Bolivian RamCompatibleNo conflicts found
Bronze CoryCompatibleNo conflicts found
Buenos Aires TetraCompatibleNo conflicts found
Cardinal TetraCompatibleNo conflicts found
Cherry BarbCompatibleNo conflicts found
Chili RasboraCompatibleNo conflicts found
Clown LoachCompatibleNo conflicts found
Clown PlecoCompatibleNo conflicts found
Cockatoo Dwarf CichlidCompatibleNo conflicts found
Congo TetraCompatibleNo conflicts found
Diamond TetraCompatibleNo conflicts found
Dwarf GouramiCompatibleNo conflicts found
Dwarf Neon RainbowfishCompatibleNo conflicts found
Electric Blue AcaraCompatibleNo conflicts found
Ember TetraCompatibleNo conflicts found
Firemouth CichlidCompatibleNo conflicts found
German Blue RamCompatibleNo conflicts found
Glowlight TetraCompatibleNo conflicts found
Harlequin RasboraCompatibleNo conflicts found
Head-and-tail-light TetraCompatibleNo conflicts found
Honey GouramiCompatibleNo conflicts found
Japanese Trapdoor SnailCompatibleNo conflicts found
KribensisCompatibleNo conflicts found
Lambchop RasboraCompatibleNo conflicts found
Lemon TetraCompatibleNo conflicts found
Marbled HatchetfishCompatibleNo conflicts found
Moonlight GouramiCompatibleNo conflicts found
Pea PufferCompatibleNo conflicts found
Pearl GouramiCompatibleNo conflicts found
Penguin TetraCompatibleNo conflicts found
Pristella TetraCompatibleNo conflicts found
Serpae TetraCompatibleNo conflicts found
Silver HatchetfishCompatibleNo conflicts found
Silver Tip TetraCompatibleNo conflicts found
Sparkling GouramiCompatibleNo conflicts found
Sterbai CoryCompatibleNo conflicts found
Three-spot GouramiCompatibleNo conflicts found
Upside-down CatfishCompatibleNo conflicts found
Yoyo LoachCompatibleNo conflicts found
Amano ShrimpCautionDiscus and Amano Shrimp only share 79–80°F. That's a tight window.; Discus may eat baby Amano Shrimp. Adults are usually safe, but expect fewer shrimplets.
Assassin SnailCautionDiscus and Assassin Snail only share 79–80°F. That's a tight window.; Discus (pH 5–7) and Assassin Snail (pH 7.5–8) prefer different pH.
Bamboo ShrimpCautionDiscus may eat baby Bamboo Shrimp. Adults are usually safe, but expect fewer shrimplets.; Discus (0–5 dGH) and Bamboo Shrimp (6–10 dGH) prefer different water hardness.
Black Skirt TetraCautionDiscus and Black Skirt Tetra only share 79–79°F. That's a tight window.
Blood Parrot CichlidCautionDiscus and Blood Parrot Cichlid only share 79–80°F. That's a tight window.
Boesemani RainbowfishCautionDiscus (0–5 dGH) and Boesemani Rainbowfish (9–20 dGH) prefer different water hardness.
Bristlenose PlecoCautionDiscus and Bristlenose Pleco only share 79–79°F. That's a tight window.
Bumblebee GobyCautionDiscus (0–5 dGH) and Bumblebee Goby (8–20 dGH) prefer different water hardness.
Celestial Pearl DanioCautionDiscus and Celestial Pearl Danio only share 79–79°F. That's a tight window.
Cherry ShrimpCautionDiscus may eat baby Cherry Shrimp. Adults are usually safe, but expect fewer shrimplets.; Discus (0–5 dGH) and Cherry Shrimp (6–14 dGH) prefer different water hardness.
Clown KillifishCautionDiscus and Clown Killifish only share 79–79°F. That's a tight window.
Common PlecoCautionDiscus and Common Pleco only share 79–79°F. That's a tight window.; Discus (0–5 dGH) and Common Pleco (10–20 dGH) prefer different water hardness.
Electric Yellow LabCautionDiscus (pH 5–7) and Electric Yellow Lab (pH 7.7–8.6) prefer different pH.; Discus (0–5 dGH) and Electric Yellow Lab (10–25 dGH) prefer different water hardness.
Endler's LivebearerCautionDiscus (0–5 dGH) and Endler's Livebearer (15–35 dGH) prefer different water hardness.
Forktail Blue-eyeCautionDiscus (0–5 dGH) and Forktail Blue-eye (15–30 dGH) prefer different water hardness.
Ghost ShrimpCautionDiscus may eat baby Ghost Shrimp. Adults are usually safe, but expect fewer shrimplets.
Giant DanioCautionDiscus and Giant Danio only share 79–79°F. That's a tight window.
Glass CatfishCautionDiscus and Glass Catfish only share 79–79°F. That's a tight window.
GuppyCautionDiscus (0–5 dGH) and Guppy (8–30 dGH) prefer different water hardness.
Iridescent SharkCautionDiscus and Iridescent Shark only share 79–79°F. That's a tight window.
Julii CoryCautionDiscus and Julii Cory only share 79–79°F. That's a tight window.
Kissing GouramiCautionKissing Gourami can bully smaller, peaceful Discus.
Kuhli LoachCautionDiscus and Kuhli Loach only share 79–79°F. That's a tight window.
Malaysian Trumpet SnailCautionDiscus and Malaysian Trumpet Snail only share 79–80°F. That's a tight window.
MollyCautionDiscus (0–5 dGH) and Molly (15–30 dGH) prefer different water hardness.
OscarCautionOscar can bully smaller, peaceful Discus.
OtocinclusCautionDiscus and Otocinclus only share 79–79°F. That's a tight window.
Peppered CoryCautionDiscus and Peppered Cory only share 79–79°F. That's a tight window.
PlatyCautionDiscus and Platy only share 79–79°F. That's a tight window.; Discus (0–5 dGH) and Platy (10–30 dGH) prefer different water hardness.
Pygmy CoryCautionDiscus and Pygmy Cory only share 79–79°F. That's a tight window.
Rainbow SharkCautionDiscus and Rainbow Shark only share 79–79°F. That's a tight window.
Ramshorn SnailCautionDiscus (0–5 dGH) and Ramshorn Snail (8–18 dGH) prefer different water hardness.
Red-Tail SharkCautionDiscus and Red-Tail Shark only share 79–79°F. That's a tight window.
Rummy-nose TetraCautionDiscus and Rummy-nose Tetra only share 79–79°F. That's a tight window.
Siamese Algae EaterCautionDiscus and Siamese Algae Eater only share 79–79°F. That's a tight window.
SwordtailCautionDiscus (0–5 dGH) and Swordtail (10–25 dGH) prefer different water hardness.
Tiger BarbCautionDiscus and Tiger Barb only share 79–79°F. That's a tight window.
Variatus PlatyCautionDiscus and Variatus Platy only share 79–79°F. That's a tight window.; Discus (0–5 dGH) and Variatus Platy (14–30 dGH) prefer different water hardness.
African Dwarf FrogAvoidDiscus (79–86°F) and African Dwarf Frog (74–77°F) need different temperatures.
Chinese Algae EaterAvoidDiscus and Chinese Algae Eater only share 79–79°F. That's a tight window.; Chinese Algae Eater is aggressive toward tankmates. Discus is peaceful.
Common / Comet GoldfishAvoidDiscus (79–86°F) and Common / Comet Goldfish (68–75°F) need different temperatures.
Convict CichlidAvoidConvict Cichlid is aggressive toward tankmates. Discus is peaceful.
Crystal Red ShrimpAvoidDiscus (79–86°F) and Crystal Red Shrimp (71–76°F) need different temperatures.; Discus may eat baby Crystal Red Shrimp. Adults are usually safe, but expect fewer shrimplets.
Denison BarbAvoidDiscus (79–86°F) and Denison Barb (59–77°F) need different temperatures.
Fancy GoldfishAvoidDiscus (79–86°F) and Fancy Goldfish (50–70°F) need different temperatures.
Gold BarbAvoidDiscus (79–86°F) and Gold Barb (61–75°F) need different temperatures.
Hillstream LoachAvoidDiscus (79–86°F) and Hillstream Loach (68–75°F) need different temperatures.
Mystery SnailAvoidDiscus (79–86°F) and Mystery Snail (70–78°F) need different temperatures.; Discus (pH 5–7) and Mystery Snail (pH unknown) prefer different pH.
Neon TetraAvoidDiscus (79–86°F) and Neon Tetra (70–77°F) need different temperatures.
Nerite SnailAvoidDiscus (79–86°F) and Nerite Snail (72–78°F) need different temperatures.; Discus (pH 5–7) and Nerite Snail (pH 8–8.4) prefer different pH.
Odessa BarbAvoidDiscus (79–86°F) and Odessa Barb (61–77°F) need different temperatures.
Panda CoryAvoidDiscus (79–86°F) and Panda Cory (72–77°F) need different temperatures.
Paradise FishAvoidDiscus (79–86°F) and Paradise Fish (50–72°F) need different temperatures.
Pearl DanioAvoidDiscus (79–86°F) and Pearl Danio (61–77°F) need different temperatures.
Pictus CatfishAvoidDiscus (79–86°F) and Pictus Catfish (72–77°F) need different temperatures.
Rosy BarbAvoidDiscus (79–86°F) and Rosy Barb (61–75°F) need different temperatures.
Scissortail RasboraAvoidDiscus (79–86°F) and Scissortail Rasbora (72–77°F) need different temperatures.
Tinfoil BarbAvoidDiscus (79–86°F) and Tinfoil Barb (72–77°F) need different temperatures.
Weather LoachAvoidDiscus (79–86°F) and Weather Loach (64–74°F) need different temperatures.
White Cloud Mountain MinnowAvoidDiscus (79–86°F) and White Cloud Mountain Minnow (57–72°F) need different temperatures.
Zebra DanioAvoidDiscus (79–86°F) and Zebra Danio (64–77°F) need different temperatures.

Care notes

Needs: Warm, soft, acidic water and an established, very clean tank; shy and skittish - needs lots of cover (heavy planting) and calm tankmates.

Group: SF rates it as needing to be in a group and says wild fish school; number not stated; 6 editorial. SF's 255 L tank is described as suitable for a few juveniles or one breeding pair, so a group of adults needs more space.

Temperament: peaceful toward other fish, semi-aggressive toward its own kind. Lives in the middle of the tank.

Common questions

How big does a Discus get?

About 6.6 inches (14 cm SL) as an adult, according to seriouslyfish.com.

What size tank does a Discus need?

At least 47 inches long and about 67 gallons. The smallest standard tank that meets that is a 75 gallon.

How many Discuss should be kept together?

At least 6. SF rates it as needing to be in a group and says wild fish school; number not stated; 6 editorial. SF's 255 L tank is described as suitable for a few juveniles or one breeding pair, so a group of adults needs more space.

What fish can live with a Discus?

Species that passed every check include Cardinal Tetra, Harlequin Rasbora, Ember Tetra, Chili Rasbora, Cherry Barb, Black Neon Tetra.

Gear for a Discus setup

TankSmallest standard tank that meets its minimum: 75 gallon (48 in long).Find on Amazon →HeaterAbout 2 × 200 W for 75 gallons, holding 79–86°F.Find on Amazon →FoodMeaty frozen foods suit its diet.Find on Amazon →Test kitCheck ammonia, nitrite and pH. Cycle the tank before adding fish.Find on Amazon →

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Related guides

Discus suppliesBlackwater biotope tanksCichlid tank guideCommunity tank fish

Sources

Values come from these pages, in our own words. Status: verified (independent spot-check). Last reviewed 2026-10-12.