TankStockingDiscus Tank Mates
Discus are large, stunning, demanding cichlids — peaceful, but only for keepers who can meet their exacting needs.
They are gentle and best kept in a group, but they require very warm (28–30 °C), soft, spotless water and grow to 20 cm, which rules out many tankmates on temperature and bio-load grounds. The engine clears warm-water companions like cardinal tetras and other discus, and flags cooler-water fish. This is an advanced fish, not a beginner one.
Discus key facts
The sourced figures the engine uses to judge Discus pairings.
| Adult size | 20 cm |
|---|---|
| Minimum tank | 75 US gal |
| Minimum group | 6+ (shoal) |
| Temperament | Peaceful |
| Temperature range | 28–30°C |
| pH range | 6–7.5 |
| Bioload | High |
| Swim level | Midwater |
| Beginner-friendly | No — advanced |
Sources & confidence (9 species)
These back the Discus figures and the recommended tank mates above. Each figure is read from the TankStocking species database (v2026.06); below is the care reference behind it and how confident we are in that data. Confidence reflects the source quality, not whether any pairing is safe. Full source list and the welfare model are on the methodology page.
- Discus Symphysodon aequifasciatus — Aquarium Co-Op (aquariumcoop.com/blogs/aquarium/discus-care-guide); FishLore high confidence
- Moonlight Gourami Trichopodus microlepis — Seriously Fish (seriouslyfish.com/species/trichopodus-microlepis) high confidence
- Snakeskin Gourami Trichopodus pectoralis — Seriously Fish (seriouslyfish.com/species/trichopodus-pectoralis) high confidence
- Kuhli Loach Pangio kuhlii — Seriously Fish / FishBase (Pangio kuhlii) high confidence
- Cardinal Tetra Paracheirodon axelrodi — Seriously Fish (seriouslyfish.com/species/paracheirodon-axelrodi) high confidence
- German Blue Ram Mikrogeophagus ramirezi — Seriously Fish (seriouslyfish.com/species/mikrogeophagus-ramirezi) high confidence
- Threadfin Rainbowfish Iriatherina werneri — Seriously Fish (seriouslyfish.com/species/iriatherina-werneri) high confidence
- Freshwater Angelfish Pterophyllum scalare — Seriously Fish (seriouslyfish.com/species/pterophyllum-scalare) high confidence
- Green Severum Heros efasciatus — Seriously Fish (seriouslyfish.com/species/heros-efasciatus) high confidence
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Verdict
Top Discus tank mates
A ranked shortlist: the species the engine clears with Discus and that suit its size and temperament best — tap a name for its care guide, or use + Add to test the pairing in the planner.
| Species | Adult size | Temp range | Min group | Swim level | Why it works | Plan |
|---|---|---|---|---|---|---|
| Moonlight Gourami | 15 cm | 25–30°C | 1 | Midwater | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
| Snakeskin Gourami | 25 cm | 22–30°C | 1 | Midwater | peacefulsize-safePeaceful temperament, similar adult size | + Add |
| Kuhli Loach | 9 cm | 24–30°C | 5+ (shoal) | Bottom | different swim levelpeacefulbeginner-friendlyUses the bottom zone, peaceful temperament | + Add |
| Cardinal Tetra | 3 cm | 23–29°C | 6+ (shoal) | Midwater | peacefulbeginner-friendlyPeaceful temperament | + Add |
| German Blue Ram | 5 cm | 27–30°C | 2+ (pair/group) | Bottom | different swim levelpeacefulUses the bottom zone, peaceful temperament | + Add |
| Threadfin Rainbowfish | 4 cm | 22–30°C | 6+ (shoal) | Midwater | peacefulPeaceful temperament | + Add |
| Freshwater Angelfish | 15 cm | 24–30°C | 1 | Midwater | size-safebeginner-friendlySimilar adult size | + Add |
| Green Severum | 30 cm | 24–29°C | 1 | All levels | size-safebeginner-friendlySimilar adult size | + Add |
No tank mates match these filters — try removing one.
Possible with care
These can work, but the engine flags something to watch — read the reason before you commit.
- Cockatoo Dwarf Cichlid (Apisto Cacatuoides) — Territorial
- Firemouth Cichlid — Territorial
Best avoided
A hard welfare check fires for each of these — don't mix them with Discus.
- Banded Gourami — Temperature clash
- Betta (Siamese Fighting Fish) — Temperature clash, Territorial
- Chocolate Gourami — Species-only fish
- Croaking Gourami — Temperature clash
- Dwarf Gourami — Temperature clash
- Honey Gourami — Temperature clash
- Licorice Gourami — Temperature clash, Species-only fish
- Paradise Fish — Temperature clash, Aggression
- Peaceful Betta (Crescent Betta) — Temperature clash
- Pearl Gourami — Temperature clash
- Sparkling (Pygmy) Gourami — Temperature clash
- Three-spot (Blue/Opaline/Gold) Gourami — Temperature clash
- Bala Shark — Temperature clash
- Checker Barb — Temperature clash
Keeping Discus well: the detail
Beyond the table — the behaviour, the parameters that actually move the needle, and the mistakes that cost fish. Hobbyist context, not a verdict; the planner above is what judges your plan.
Water parameters in practice
Discus demand very warm (28–30 °C), soft, acidic, and immaculate water — the highest-maintenance parameters on this list. The heat speeds up everything, so frequent large water changes and a mature, stable system are part of the deal, not extras. This is an advanced fish; the parameter that matters most is the keeper's discipline.
Why Discus behaves the way it does
Discus are tall, disc-shaped cichlids from the warm, soft, slow blackwaters of the Amazon, where they live in groups among submerged wood and roots. The need for heat and softness, the sensitivity to stress, and the group-living instinct all come straight from that habitat. They are peaceful but establish a pecking order, so a lone or paired discus can be bullied.
Common Discus stocking mistakes
The first mistake is keeping discus as a beginner or in a new tank — they need experience and a fully mature system. The second is too small a group; fewer than five lets a dominant fish harass the rest, so keep five or six. The third is cool or unstable water, which they will not forgive.
Early signs something is wrong
A discus that darkens, clamps its fins, hides, or refuses food is signalling stress — almost always water quality, temperature, or social pressure. They are prone to internal parasites and to "going dark and thin", so watch weight and behaviour closely. A healthy discus is bold, bright, and feeds confidently in the group.
How tank size changes the answer
A group of five or six needs at least 55 gallons, and a tall tank suits their body shape. The volume is as much about stability and dilution of waste at high temperature as about swimming room. Pair them only with warm-tolerant, peaceful dither fish like cardinal tetras.
Discus community ideas
Each build is scored by the same engine as the planner — tap one to load it.
Discus group
✓ Good starter plan6× Discus
A group of six discus in a warm, tall, planted tank — the heart of a discus display.
Load this build in the planner ↑Discus + cardinals
✓ Good starter plan6× Discus, 12× Cardinal Tetra
Cardinal tetras share the discus's warm, soft water — the classic discus dither fish.
Load this build in the planner ↑Common questions
What fish can live with discus?
Warm-water, peaceful fish that tolerate 28–30 °C: cardinal tetras, rummynose tetras, and other discus. Avoid cooler-water species and anything boisterous or nippy — discus are slow, gentle feeders.
Are discus hard to keep?
Yes — they need very warm, soft, immaculate water and frequent large water changes, plus a group for security. They are widely considered an advanced fish.
How many discus should I keep?
At least five. Discus are social and establish a pecking order; in small groups a dominant fish can bully the others, so a larger group spreads aggression.
More on Discus
Related guides on TankStocking — each scored by the same welfare engine as the planner.
Care guides
Compatibility checks
Browse all fish
Compatibility is a planning estimate: individual temperament, tank layout, and group sizes all matter. Cycle the tank, add fish gradually, and watch how they behave. See the methodology or browse the full freshwater fish list.