Can Cardinal Tetra live with Carnival / Polka Dot Freshwater Crab?
Caution — with care
Why
- Carnival / Polka Dot Freshwater Crab can grab Cardinal Tetra while it sleeps — only fast mid/top-water fish are reasonably safe.
- No overlapping pH: Cardinal Tetra wants 5–7 but Carnival / Polka Dot Freshwater Crab wants 7.5–8.
- No overlapping water hardness: Cardinal Tetra wants 1–6 dGH but Carnival / Polka Dot Freshwater Crab wants 8–15 dGH.
Side-by-side
| Cardinal Tetra | Carnival / Polka Dot Freshwater Crab | |
|---|---|---|
| Temperature | 73–81°F | 75–82°F |
| pH | 5–7 | 7.5–8 |
| Hardness (GH) | 1–6 dGH | 8–15 dGH |
| Adult size | 2" | 1.5" |
| Temperament | Peaceful | Peaceful |
| Min tank | 15 gal | 10 gal |
Together, plan on at least 15 gallons.
How to make it work
- Only combine with fast, mid/top-water fish and give the tankmates plenty of escape routes.
- Target the overlapping water-parameter range and acclimate slowly.
Sort it with: GH remineraliser
Where to buy
- Cardinal Tetra: buy at The Shrimp Farm · The Shrimp Farm live-arrival guarantee
Live-animal shipping: add a heat pack below 50°F, expect weather holds above 90°F, and schedule delivery for a moderate week when someone can receive it promptly.
Design the whole tank, not just the stocking
Skapelab plans a complete, buildable planted aquarium around your fish — a hand-illustrated layout, the exact plants and hardscape, a placement map, and a full equipment and shopping list. Free.
Design a tank with Cardinal Tetra, Carnival / Polka Dot Freshwater Crab →Everything compatible with Cardinal Tetra · …with Carnival / Polka Dot Freshwater Crab