TankStockingCardinal Tetra Tank Mates
Cardinal tetras are stunning, peaceful schoolers — like neons, but a touch larger and happier in warm, soft water.
They are gentle and easy to stock around, with the same one caveat as neons: keep them away from anything big enough to eat them. The engine clears small, peaceful community fish and flags larger predators. A big school in a planted tank is one of the hobby's great sights.
Cardinal Tetra key facts
The sourced figures the engine uses to judge Cardinal Tetra pairings.
| Adult size | 3 cm |
|---|---|
| Minimum tank | 15 US gal |
| Minimum group | 6+ (shoal) |
| Temperament | Peaceful |
| Temperature range | 23–29°C |
| pH range | 4–7.5 |
| Bioload | Low |
| Swim level | Midwater |
| Beginner-friendly | Yes |
Sources & confidence (11 species)
These back the Cardinal Tetra 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.
- Cardinal Tetra Paracheirodon axelrodi — Seriously Fish (seriouslyfish.com/species/paracheirodon-axelrodi) high confidence
- Amano Shrimp Caridina multidentata — Aquarium Co-Op amano shrimp care; Aquadiction high confidence
- Assassin Snail Clea helena (Anentome helena) — The Shrimp Farm (theshrimpfarm.com/posts/assassin-snail-care) high confidence
- Black Neon Tetra Hyphessobrycon herbertaxelrodi — Seriously Fish / Aqua-Fish (Hyphessobrycon herbertaxelrodi) high confidence
- Black Phantom Tetra Hyphessobrycon megalopterus — Seriously Fish (Hyphessobrycon megalopterus) high confidence
- Bleeding Heart Tetra Hyphessobrycon erythrostigma — Seriously Fish (Hyphessobrycon erythrostigma) high confidence
- Celestial Pearl Danio Celestichthys margaritatus — Seriously Fish (seriouslyfish.com/species/celestichthys-margaritatus) high confidence
- Checker Barb Oliotius oligolepis — Seriously Fish — Oliotius oligolepis (https://www.seriouslyfish.com/species/oliotius-oligolepis/) high confidence
- Cherry Barb Puntius titteya — Seriously Fish (Puntius titteya) seriouslyfish.com/species/puntius-titteya high confidence
- Cherry Shrimp Neocaridina davidi — Aquarium Co-Op cherry shrimp care; The Shrimp Farm high confidence
- Chili Rasbora Boraras brigittae — Seriously Fish (seriouslyfish.com/species/boraras-brigittae) high confidence
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Verdict
Top Cardinal Tetra tank mates
A ranked shortlist: the species the engine clears with Cardinal Tetra 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 |
|---|---|---|---|---|---|---|
| Amano Shrimp | 5 cm | 18–27°C | 3+ (pair/group) | All levels | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
| Assassin Snail | 2 cm | 18–25°C | 1 | Bottom | different swim levelpeacefulsize-safebeginner-friendlyUses the bottom zone, peaceful temperament, similar adult size | + Add |
| Black Neon Tetra | 3.5 cm | 23–27°C | 6+ (shoal) | Midwater | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
| Black Phantom Tetra | 3.6 cm | 20–28°C | 6+ (shoal) | Midwater | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
| Bleeding Heart Tetra | 6 cm | 21–28°C | 8+ (shoal) | Midwater | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
| Celestial Pearl Danio | 2.1 cm | 20–26°C | 8+ (shoal) | Midwater | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
| Checker Barb | 5 cm | 20–25°C | 6+ (shoal) | Midwater | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
| Cherry Barb | 5 cm | 23–27°C | 6+ (shoal) | Midwater | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
| Cherry Shrimp | 3 cm | 18–28°C | 6+ (pair/group) | All levels | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
| Chili Rasbora | 2 cm | 20–28°C | 8+ (shoal) | Midwater | peacefulsize-safebeginner-friendlyPeaceful temperament, similar adult size | + Add |
No tank mates match these filters — try removing one.
Other engine-cleared options (not necessarily ideal)
These clear TankStocking's hard welfare checks with Cardinal Tetra, but are larger, bolder, or otherwise less ideal than the shortlist above — read up before committing.
Anabantoids (Bettas/Gouramis)
Corydoras
Invertebrates
Livebearers
Loaches
Oddball
Plecos & Catfish
Rasboras
Possible with care
These can work, but the engine flags something to watch — read the reason before you commit.
- Betta (Siamese Fighting Fish) — Territorial
- Paradise Fish — Aggression
- Cockatoo Dwarf Cichlid (Apisto Cacatuoides) — Territorial
- Kribensis (Rainbow Krib) — Territorial
Best avoided
A hard welfare check fires for each of these — don't mix them with Cardinal Tetra.
- Chocolate Gourami — Species-only fish
- Kissing Gourami — Predation risk
- Licorice Gourami — Species-only fish
- Snakeskin Gourami — Predation risk
- Three-spot (Blue/Opaline/Gold) Gourami — Predation risk
- Bala Shark — Predation risk
- Denison Barb (Roseline Shark) — Predation risk
- Rosy Barb — Predation risk
- Tinfoil Barb — Predation risk
- Convict Cichlid — Predation risk, Aggression
- Electric Blue Acara — Predation risk
- Firemouth Cichlid — Predation risk, Territorial
- Freshwater Angelfish — Predation risk
- Green Severum — Predation risk
Keeping Cardinal Tetra 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
Cardinals want warm, soft, acidic water — 25–28 °C and soft (under ~6 dGH), warmer and softer than neons, with which they are often muddled. They reward a mature, tannin-stained, planted tank and resent fresh, hard, alkaline water. Buy tank-bred stock if you can: wild-caught cardinals are beautiful but sensitive, while captive-bred are far hardier.
Why Cardinal Tetra behaves the way it does
Cardinal tetras come from the warm blackwater tributaries of the upper Rio Negro, mineral-poor and tea-coloured with leaf tannins, where they shoal over submerged litter in dim light. The full-length red stripe and the love of warmth and softness are direct readouts of that habitat. Recreate the dim, soft, warm conditions and the colour is extraordinary.
Common Cardinal Tetra stocking mistakes
The first mistake is treating a cardinal like a neon and keeping it too cool — they want the warm end. The second is adding wild-caught fish to an immature tank, where they fade and fail. The third is the same predation trap as neons: anything large-mouthed will eat a 3 cm cardinal.
Early signs something is wrong
A fading stripe, a fish swimming apart, and clamped fins are the early signs, usually pointing to cool or unstable water rather than disease. Wild stock is prone to internal parasites, so watch for thinness and stringy waste in new arrivals and quarantine them. A settled cardinal school glows and moves as one.
How tank size changes the answer
A school of six fits 15 gallons, but cardinals are made to be shown in numbers — a dozen or more in a 20-gallon-plus planted tank is one of the hobby's best sights. More water also holds the warmth and softness steadier, which this fish appreciates. Stock the group large and the tank dim.
Cardinal Tetra community ideas
Each build is scored by the same engine as the planner — tap one to load it.
Cardinal + cory
✓ Good starter plan10× Cardinal Tetra, 6× Bronze Corydoras
A glowing mid-water school over a bottom shoal — a planted-tank classic.
Load this build in the planner ↑Cardinal + ram
✓ Good starter plan10× Cardinal Tetra, 2× German Blue Ram
A dwarf-cichlid pair with a cardinal school, all thriving in warm, soft water.
Load this build in the planner ↑Common questions
What fish can live with cardinal tetras?
Small, peaceful community fish: corydoras, rasboras, dwarf cichlids such as rams, honey gouramis, and peaceful shrimp. Keep tankmates small enough that they cannot eat a cardinal.
Are cardinal tetras the same as neon tetras?
They are similar but distinct: cardinals are slightly larger, have red running the full length of the body, and prefer warmer, softer water. They are also a little hardier once settled.
How many cardinal tetras should I keep?
At least six, and a dozen or more for the best effect. Cardinals are shoaling fish that colour up and behave naturally only in a proper group.
More on Cardinal Tetra
Related guides on TankStocking — each scored by the same welfare engine as the planner.
Care guides
Compatibility checks
Stocking by tank size
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.