Yes, you absolutely can put coral in a saltwater tank, provided that the salt content and temperature in your aquarium are correct. In fact, once your tank's water parameters are stable and the substrate has settled and the water is clear, you can begin introducing corals, transforming your aquarium into a vibrant reef ecosystem.
Keeping corals is a rewarding aspect of saltwater aquaria, but it requires diligent monitoring and maintenance to ensure these delicate marine invertebrates thrive.
Key Considerations Before Adding Corals
Before introducing any corals, it's crucial to establish a stable and mature environment that mimics their natural ocean habitat.
Establishing a Stable Environment
A successful coral tank begins with proper preparation:
- Tank Cycling: Ensure your aquarium has completed its nitrogen cycle. This process establishes beneficial bacteria that convert toxic ammonia and nitrites into less harmful nitrates, creating a stable biological filter essential for coral health.
- Maturity: A newly cycled tank might be biologically stable, but a tank that has been running for several months often provides a more robust and forgiving environment for corals. This allows for parameter stability and the establishment of microfauna.
Crucial Water Parameters
Maintaining consistent water quality is paramount for coral survival. Regular testing and adjustments are necessary.
| Parameter | Ideal Range | Importance |
|---|---|---|
| Salinity | 1.025 – 1.026 SG | Essential for cellular function and calcification. Measured with a refractometer or hydrometer. |
| Temperature | 75-82°F (24-28°C) | Corals are sensitive to temperature fluctuations; stable range prevents stress and bleaching. |
| Alkalinity (dKH) | 8 – 12 dKH | Supports calcification and buffers pH. Critical for stony coral skeletal growth. |
| Calcium (Ca) | 400 – 450 ppm | Primary building block for stony coral skeletons. Works in tandem with alkalinity and magnesium. |
| Magnesium (Mg) | 1250 – 1350 ppm | Facilitates the uptake of calcium and alkalinity, preventing their precipitation. |
| Nitrates (NO3) | 0 – 10 ppm (low but not zero) | Excess can inhibit coral growth, but some is beneficial for nutrient uptake by zooxanthellae (symbiotic algae). |
| Phosphates (PO4) | 0.03 ppm or lower | High levels can stunt growth and promote nuisance algae. |
- Monitoring: Use reliable test kits to regularly check these parameters. Consistency is key, as sudden swings can be detrimental.
- Top-Off Water: Use only purified Reverse Osmosis/Deionized (RO/DI) water for evaporation top-offs to prevent the buildup of unwanted minerals and chemicals.
Choosing the Right Corals
Corals vary widely in their care requirements, making it important to select species appropriate for your experience level and tank conditions.
Types of Corals
- Soft Corals: These are often recommended for beginners due to their hardiness and less stringent water quality demands. Examples include Zoanthids, Mushroom Corals, and Leather Corals. They typically don't build stony skeletons, relying more on absorption of nutrients and light.
- Large Polyp Stony (LPS) Corals: LPS corals have larger, fleshy polyps and build calcium carbonate skeletons. They require stable water parameters but are generally more forgiving than SPS corals. Popular examples include Euphyllia (Hammer, Torch, Frogspawn), Acanthastrea, and Favia.
- Small Polyp Stony (SPS) Corals: SPS corals are the most demanding, requiring pristine water, strong lighting, and precise water flow. They are characterized by tiny polyps and rapid skeletal growth. Acropora and Montipora are classic examples, often sought after by experienced reef keepers.
For more detailed information on coral types, you can consult resources like the Reef Builders Guide to Corals.
Acclimating New Corals
Proper acclimation is vital to minimize stress on new corals, helping them adjust to your tank's unique water parameters.
Step-by-Step Acclimation Process
- Temperature Acclimation: Float the sealed bag containing the coral in your tank for 15-20 minutes to equalize temperatures.
- Drip Acclimation: Slowly introduce tank water into the bag over 30-60 minutes using an airline tube and a drip valve. This gradual process helps the coral adjust to changes in salinity and pH. Avoid exposing the coral directly to air if possible, especially stony corals.
- Dipping: Consider dipping new corals in a coral dip solution (available at aquarium stores) to help remove common pests like predatory flatworms or nudibranchs before introduction.
- Placement: Gently place the coral in its desired location in the tank.
Optimal Placement in the Aquarium
Coral placement is crucial for their long-term health:
- Lighting: Different corals have varying light requirements. Place high-light demanding corals (e.g., SPS) higher in the tank and directly under intense light, while low-light corals (e.g., some soft corals, LPS) can be placed lower or in shaded areas.
- Water Flow: Ensure adequate and appropriate water flow. Some corals prefer strong, turbulent flow (many SPS), while others prefer gentle, indirect flow (some LPS and soft corals). Flow helps bring food and remove waste.
- Space for Growth: Account for future growth and ensure corals have enough space to expand without touching neighboring corals, which can lead to chemical warfare.
Ongoing Coral Care and Maintenance
Maintaining a thriving reef tank is an ongoing commitment to providing optimal conditions.
Lighting
Investing in high-quality aquarium lighting (LED, T5, or Metal Halide) that provides the correct spectrum and intensity is crucial. Most corals host symbiotic algae (zooxanthellae) that rely on light for photosynthesis. Establish a consistent photoperiod, typically 8-12 hours per day.
Water Flow
Ensure your tank has adequate water movement using powerheads or wavemakers. Varied flow patterns are beneficial, preventing detritus buildup and ensuring corals receive necessary nutrients and dispel waste.
Feeding and Supplementation
While many corals primarily get energy from light, target feeding with specialized coral foods (phytoplankton, zooplankton, or amino acids) can enhance growth and vibrancy, especially for LPS and some soft corals. Additionally, regular supplementation of calcium, alkalinity, and magnesium might be necessary in tanks with significant stony coral growth.
Regular Maintenance
Consistent maintenance practices are key:
- Water Changes: Perform regular partial water changes (e.g., 10-20% bi-weekly or monthly) to replenish trace elements and remove accumulated nitrates and phosphates.
- Filter Maintenance: Clean filter socks, skimmer cups, and other filtration media regularly to maintain water quality.
- Pest Control: Regularly inspect your corals for signs of pests or diseases and address them promptly.
By understanding these fundamentals, you can successfully keep and grow a diverse array of corals in your saltwater tank, creating a stunning and dynamic underwater display.
