Common name: Shoulderblade Coral

General Information

Pavona clavus, commonly known as Shoulderblade Coral or Swollen Coral, is a small polyp stony (SPS) coral species belonging to the family Agariciidae. It is widely distributed across the Indo-Pacific region, including the Red Sea, the Indian Ocean, and the western and central Pacific Ocean. This coral is known for its robust growth forms, which vary based on its environment and include encrusting, boulder-like, or plate-like structures. Its thick, leafy plates often overlap, creating a layered appearance that offers excellent shelter for small reef inhabitants, making it a striking addition to reef aquariums.

This species is highly valued by reefkeepers for its resilience and ability to adapt to various lighting and flow conditions. However, its large size and relatively slow growth rate mean it requires careful placement and maintenance to thrive in a home aquarium. Its natural habitat includes reef slopes and lagoons, where it can be found at depths ranging from shallow waters to over 30 meters.

World’s Largest Coral

In October 2024, scientists from National Geographic Society’s Pristine Seas expedition discovered the world’s largest known coral colony, a Pavona clavus, near the Solomon Islands in the southwest Pacific Ocean. This massive coral measures approximately 34 by 32 meters (112 by 105 feet) and stands 5 meters tall (16 feet), making it one of the most impressive marine discoveries of the decade. Estimated to be over 300 years old, this ancient coral has endured significant environmental changes, showcasing extraordinary resilience.

Located at a depth of about 13 meters (42 feet), the coral’s position may have shielded it from the adverse effects of warming sea temperatures that typically impact shallower reefs. The health of this coral is encouraging; it provides essential habitat, shelter, and breeding grounds for various marine species, including shrimp, crabs, and fish. However, despite its relatively remote location, it remains vulnerable to climate change and human activities, highlighting the ongoing need for marine conservation efforts.

This extraordinary discovery underscores the importance of protecting coral reefs and their ecosystems. The Pavona clavus serves as a beacon of hope and a reminder of the urgent need to safeguard our oceans for future generations.

Care

Pavona clavus is considered moderately easy to care for, making it suitable for aquarists with some experience. It thrives in stable water conditions with moderate to high flow and lighting. This coral is photosynthetic, relying on its symbiotic zooxanthellae algae for energy, but it can also benefit from supplemental feeding of fine particulate foods like phytoplankton or coral-specific liquid feeds.

When placing Pavona clavus in your aquarium, ensure it has enough space to grow without being overshadowed by other corals. Its encrusting and plating growth forms can spread over nearby rockwork, so plan its placement carefully to avoid competition with other species.

Diet and Feeding

As a photosynthetic coral, Pavona clavus derives most of its energy from the light-driven activities of its zooxanthellae. However, it can also capture fine particulate matter and plankton from the water column. Target feeding with coral-specific foods can enhance its growth and coloration, especially in lower-light setups.

Feed Pavona clavus once or twice a week, ensuring the food particles are small enough to be absorbed by its polyps. Avoid overfeeding, as excess nutrients can lead to algae growth and water quality issues.

Behavior and Compatibility

Pavona clavus is generally peaceful but can exhibit mild aggression through its sweeper tentacles, which it uses to defend its space. It is best placed at a distance from other corals to prevent potential conflicts. This coral is compatible with a wide range of reef-safe fish and invertebrates, making it a versatile choice for community reef tanks.

Its layered growth form provides shelter for small fish and invertebrates, adding to the biodiversity of your aquarium. However, its encrusting nature means it can overgrow nearby corals if not kept in check.

Propagation

Pavona clavus can be propagated through fragging, a process where small pieces of the coral are carefully cut and attached to new substrates. This method allows aquarists to share or trade fragments with others while promoting sustainable reefkeeping practices. Ensure the fragging tools are clean and the coral is given time to recover in stable water conditions.

Symbiosis

Like many corals, Pavona clavus has a symbiotic relationship with zooxanthellae algae, which live within its tissues. These algae perform photosynthesis, providing the coral with essential nutrients while benefiting from the coral's protection and access to sunlight. This mutualistic relationship is vital for the coral's survival and growth.

Health and Common Issues

Pavona clavus is relatively hardy but can be susceptible to common coral ailments such as tissue recession, bleaching, and pest infestations. Maintaining stable water parameters, including proper alkalinity, calcium, and magnesium levels, is crucial for its health. Regular monitoring and prompt action can prevent most issues.

When selecting a specimen, look for vibrant coloration and fully extended polyps, which indicate good health. Avoid corals with signs of tissue damage or bleaching.

Habitat

In the wild, Pavona clavus inhabits reef slopes and lagoons, often in areas with moderate to strong water flow. Its natural range includes the Indo-Pacific region, where it thrives in warm, clear waters with ample sunlight. Replicating these conditions in your aquarium will help ensure its success.