Cardinal Tetra pH: Ideal Water pH & Hardness
Ideal pH 5.5-7 · Hardness 1-8 dGH
The Cardinal Tetra prefers soft, slightly acidic water: pH 5.5-7 at 1-8 dGH. Test your tap water first — many keepers match this range with no adjustment.
Stability beats a perfect number. Chasing pH with chemicals causes dangerous swings; if your water is close, leave it. To gently soften and lower pH use RO water, driftwood or peat; to raise it use crushed coral or aragonite.
| pH | 5.5-7 |
|---|---|
| Hardness | 1-8 dGH |
Frequently asked questions
What pH is best for Cardinal Tetra?
pH 5.5-7 with hardness 1-8 dGH.
How do I adjust pH for a Cardinal Tetra?
Favor stability: match it naturally with driftwood or RO water to lower, or crushed coral to raise, rather than pH chemicals.
More on this species: Cardinal Tetra full care guide · tank size · temperature · pH & hardness · tank mates