Freshwater vs Saltwater Aquariums
Aquariums are classified by the type of water they use: freshwater or saltwater. Each type has distinct chemical properties, inhabitants, and care requirements.
Freshwater Aquariums
- Salinity: Low or none (0 ppt)
- Typical inhabitants: Community fish, livebearers, cichlids, invertebrates like shrimp
- Plants: Most freshwater aquatics thrive in standard water
- Maintenance: Generally easier and more forgiving; water changes and filtration are key
Saltwater Aquariums
- Salinity: Moderate to high (~30–35 ppt, same as ocean)
- Typical inhabitants: Marine fish, corals, invertebrates
- Plants: Marine macroalgae or corals (instead of freshwater plants)
- Maintenance: More complex; requires careful monitoring of salinity, calcium, alkalinity, and trace elements
Key Differences
| Aspect | Freshwater | Saltwater |
|---|---|---|
| Salinity | 0 ppt | 30–35 ppt |
| Species diversity | Moderate | Very high |
| Cost & complexity | Lower | Higher |
| Water chemistry | Simple to manage | Requires monitoring multiple parameters |
| Equipment | Standard heater, filter | Protein skimmers, live rock, reef lighting |
Choosing between freshwater and saltwater depends on your experience, budget, and the type of species you want to keep. Beginners usually start with freshwater tanks due to their simplicity and lower cost.