Soft/Hard Water Fish
This table is only a rough guide and while there are fish that “could” live in different water parameters, by staying with this guide you can be assured your fish will not be stressed or live a shorter live by living in waters not native to their species.
| Fish Name | Water Hardness | pH Range |
|---|---|---|
| Angelfish | Soft to Moderately Hard | 6.5 – 7.5 |
| Betta (Siamese Fighting Fish) | Soft to Moderately Hard | 6.5 – 7.5 |
| Black Skirt Tetra | Soft to Moderately Hard | 6.0 – 7.5 |
| Bristlenose Pleco | Moderately Hard | 6.5 – 7.5 |
| Cardinal Tetra | Very Soft | 4.6 – 6.2 |
| Celestial Pearl Danio | Moderately Hard | 7.0 – 8.0 |
| Cherry Barb | Soft to Moderately Hard | 6.0 – 7.5 |
| Clown Loach | Soft | 6.0 – 7.5 |
| Congo Tetra | Soft to Moderately Hard | 6.0 – 7.5 |
| Corydoras Catfish | Soft | 6.0 – 7.5 |
| Denison Barb (Roseline Shark) | Moderately Hard | 6.5 – 7.8 |
| Discus | Very Soft | 6.0 – 7.0 |
| Dwarf Gourami | Soft to Moderately Hard | 6.0 – 7.5 |
| Electric Blue Acara | Soft to Hard | 6.0 – 7.5 |
| Guppy | Hard | 6.8 – 7.8 |
| Harlequin Rasbora | Soft | 6.0 – 7.0 |
| Killifish (species dependent) | Generally Soft | 6.0 – 7.0 |
| Kuhli Loach | Soft | 5.5 – 6.5 |
| Molly | Hard | 7.5 – 8.5 |
| Neon Tetra | Soft | 6.0 – 7.0 |
| Oscar | Soft to Hard | 6.0 – 8.0 |
| Otocinclus Catfish | Soft | 6.0 – 7.5 |
| Pearl Gourami | Soft to Moderately Hard | 6.5 – 8.0 |
| Platy | Hard | 7.0 – 8.2 |
| Ram Cichlid | Soft | 5.0 – 7.0 |
| Rosy Barb | Soft to Hard | 6.5 – 7.0 |
| Rummy Nose Tetra | Soft | 5.5 – 6.8 |
| Swordtail | Hard | 7.0 – 8.4 |
| Tiger Barb | Soft to Moderately Hard | 6.0 – 7.0 |
| Zebra Danio | Soft to Hard | 6.5 – 7.5 |
Understanding Water Hardness:
- Soft Water: Typically has a low concentration of dissolved minerals. Rainwater is naturally soft.
- Hard Water: Has a high concentration of dissolved minerals, particularly calcium and magnesium. Much of the tap water in the UK is hard.
It is advisable to test your tap water to understand its natural parameters. Water hardness can be adjusted using various methods, such as adding peat moss to soften it or crushed coral to harden it. Similarly, pH levels can be altered with commercially available aquarium products. Always make any changes to water chemistry gradually to avoid shocking your fish.
