Coral Types and Care in a Saltwater Aquarium

Saltwater aquariums are an aesthetic and delightful hobby for many enthusiasts. For those with a deep passion for marine life, adding corals to their aquatic setup can be a dream come true. Corals not only amplify the visual appeal of a tank but also contribute to creating a more natural environment for marine creatures. To make the most of these magnificent organisms, understanding the types of corals and their specific care requirements is vital. In this guide, we'll explore more about corals and share insights on their proper care.

Introduction to Corals

Corals are far more than just colorful additions to your aquarium. They're living organisms that typically form vast colonies that are integral to the ocean's ecosystems, often referred to as the "rainforests of the sea." Each individual coral is known as a polyp, which secretes a hard exoskeleton of calcium carbonate that contributes to the structure of coral reefs. 

For aquarium enthusiasts, corals add a level of complexity and beauty to their saltwater tanks that few other creatures can. To ensure proper care and tank management, it's crucial to understand the two types of corals.

Soft Corals

The defining characteristic of soft corals is their supple, bendable bodies. They're not supported by a rigid skeleton but may contain tiny, spike-like structures, which give them some form of support and a spiky texture. These corals are known for their ease of care and ability to adapt to various tank conditions. Here are the most prominent soft corals that are often the first choice for beginners due to their hardiness:

• Leather corals, which have a tough and leathery texture;
• Mushroom corals, which resemble terrestrial fungi in appearance; and,
• Zoanthids, which are known for their dazzling array of colors and communal growth patterns.

Hard Corals

In contrast, hard corals are the builders of the coral reef structures. Their rigid exoskeletons form the backbone of reefs and provide essential habitats for other marine life. They come in two subcategories themselves: 

• Large Polyp Stony (LPS) Corals: LPS corals, such as brain corals and hammer corals, have larger, fleshier polyps and can be a little more forgiving in a reef tank setting. 

• Small Polyp Stony (SPS) Corals: SPS corals, including staghorn corals and star corals, have smaller polyps and often require more stringent water conditions and lighting but are prized for their intricate shapes and vivid colors. These corals also demand a more nuanced level of care that appeals to advanced hobbyists.

Ideal Water Conditions for Corals

The vitality of corals in a saltwater aquarium is tightly bound to the stability and quality of the water they live in. These intricate creatures demand precise conditions to flourish, much like they would find in their natural reef habitats. Ensuring the following parameters are consistently maintained is a cornerstone of successful coral care:

• Temperature: A stable range of 75-79°F (24-26°C) mimics the tropical waters most coral species originate from. Fluctuations outside this range can stress corals, leading to bleaching or lowered immunity.
• pH Level: Corals require a slightly alkaline environment, with a pH between 8.1 and 8.4, to effectively absorb the calcium carbonate needed for skeletal formation.
• Salinity: A specific gravity of 1.023 to 1.025 not only reflects the natural saltiness of ocean water but also aids in the osmoregulation of the corals and their symbiotic algae.
• Calcium: Ranging from 400 to 450 ppm, calcium is critical for the growth of a coral's exoskeleton.
• Alkalinity: A level of 8-12 dKH helps buffer pH swings and is vital for coral growth and health.

To maintain these conditions, consistent monitoring is a must. However, the true backbone of water quality management is a robust filtration system. High-quality fish tank filters play a pivotal role in removing waste, balancing nutrients, and maintaining the overall health of the aquarium's ecosystem. 

Lighting Needs

Lighting is not just a decorative aspect of an aquarium; it's a lifeline for corals. The intensity, spectrum, and duration of lighting all influence coral health and coloration. Here's how different lighting technologies meet these needs:

• Metal Halide Lights: These provide a high-intensity output that penetrates deep water columns, making them perfect for simulating the sunlit zones of natural reefs in deeper tanks. They are especially beneficial for SPS corals that thrive in strong light.

• T5 Fluorescent Lights: A staple in coral lighting, T5s deliver a broad spectrum of light and are efficient in energy use. They distribute light evenly, catering well to a variety of corals, including LPS and soft corals that may not require intense light.

• LED Lights: Modern LED systems offer a full spectrum of light and are customizable for different times of the day to mimic natural light cycles. Their energy efficiency and low heat output make them suitable for smaller tanks where controlling temperature is critical.

Feeding Corals

Corals have diverse feeding requirements; many harbor photosynthetic algae, which produce nutrients via light, but this doesn't negate their need for direct feeding. Corals also capture particulate matter and plankton from the water. Specialized saltwater fish food, designed to mimic this natural diet, can provide essential nutrients like amino acids and lipids. 

Since coral species vary widely in their feeding habits, it's crucial to understand the particular needs of your coral species—some may benefit from targeted feeding of microplankton or other prepared coral foods, ensuring they receive the full spectrum of necessary nutrients for optimal health and growth.

Positioning Corals in the Aquarium

The strategic placement of corals within an aquarium is a critical aspect of coral care that can greatly impact their health and growth. Different species have evolved to thrive in various niches of water movement and lighting:

• Soft Corals: Generally versatile, these corals typically do well in moderate water flow, which assists in the delivery of food and the removal of waste. Placing them in areas with moderate lighting will accommodate their need for photosynthesis without the risk of bleaching that can occur under more intense light.

• LPS (Large Polyp Stony) Corals: These corals often inhabit lower energy environments in the wild, so in the aquarium, they do best in areas with gentler water flow to prevent any damage to their fleshy polyps. They also prefer moderate lighting conditions, as intense light can sometimes cause stress.

• SPS (Small Polyp Stony) Corals: In contrast to their LPS counterparts, SPS corals are adapted to high-energy environments and will flourish under strong water flow and bright light. This simulates their natural habitat on the reef crest, where water movement facilitates their high metabolic needs, and the intense lighting supports their symbiotic algae.

Understanding and replicating these conditions is essential for the well-being of the corals. Aquarists should observe their corals' responses to changes in flow and lighting to find the optimal position within the aquarium ecosystem.

Coral Compatibility

Ensuring coral compatibility is as crucial as choosing the right fish for your community tank. Many coral species are quite territorial, engaging in chemical or physical warfare for prime real estate on the reef. Some corals, particularly certain soft corals and SPS varieties, can emit harmful substances into the water to inhibit the growth of competitors, a process known as allelopathy. 

On the other hand, aggressive species might extend their stinging tentacles towards neighbors. It's paramount to research and understand the temperament and space requirements of each species to prevent such conflicts. Adequate spacing and thoughtful placement based on each species' aggression level can promote a harmonious and thriving coral community within your aquarium.

Common Coral Diseases and Their Treatment

Corals in a saltwater aquarium are susceptible to various diseases that can impede their growth and coloration, often stemming from environmental stressors. 

• White Band Disease - It manifests as stark white bands where the coral tissue peels away from the skeleton. The best approach is to carefully trim away these affected areas to prevent further spread.

• Brown Jelly Disease - This is typified by a brownish, jelly-like film and is combative through enhanced water circulation and the careful extraction of the diseased tissue. 

• Tissue Necrosis - This is rapid tissue degradation, which can often be attributed to suboptimal water conditions. Addressing this requires improving the water quality, for which reliable aquarium filters are indispensable. 

Proactive monitoring and maintaining pristine tank conditions are fundamental in the prevention and early detection of such diseases, allowing for timely and effective treatment.

Start Your Coral Journey

Corals can transform an aquarium into an underwater paradise. With proper care, knowledge, and patience, you can cultivate a vibrant, healthy coral community in your saltwater tank. Remember, each coral species has unique requirements, so thorough research is essential before making additions. Whether you're a novice or an expert aquarist, the joy of watching a flourishing coral garden is incomparable. With more knowledge, you can easily embark on this beautiful journey with corals.