Acropora Corals (Acropora spp.)

Taxonomy & Identity

Acropora is the largest and most diverse genus of stony corals, comprising the backbone of many natural reef systems. In the aquarium hobby, Acropora represents the pinnacle of SPS coral keeping. These fast-growing, colorful corals are demanding but incredibly rewarding for experienced reef keepers.

Natural Habitat & Distribution

Acropora species are found throughout tropical oceans worldwide, with the highest diversity in the Indo-Pacific region. They dominate shallow reef crests and upper slopes where light is intense and water movement is strong. Different species occupy various niches from turbulent reef flats to calmer back-reef areas.

Morphology & Growth Forms

Acropora display incredible morphological diversity: branching (staghorn), tabular (table), bushy, bottlebrush, and encrusting forms all exist. Branches typically have an axial corallite at the tip and radial corallites along the sides. Colors span the entire spectrum—blues, purples, greens, pinks, yellows, and reds in countless combinations.

Lighting Requirements & Spectrum

• Intensity: High
• Target PAR: 300–500+

Acropora demand intense lighting to thrive and display optimal coloration. Most species do best under PAR levels of 300–500, with some tolerating even higher. LED fixtures capable of high output are essential. Blue-heavy spectrums enhance fluorescent pigments while adequate white light supports photosynthesis. Acclimate new specimens slowly to prevent bleaching.

Flow Requirements & Patterns

• Intensity: High
• Type: Strong, varied, turbulent

High, turbulent flow is critical for Acropora health. Strong water movement delivers nutrients, removes waste, and prevents sediment accumulation in branches. Random, chaotic flow patterns best replicate natural reef conditions. Multiple powerheads or wave makers are typically required to achieve adequate flow throughout the colony.

Nutrient Dynamics & Water Chemistry

Acropora are demanding regarding water chemistry. Low nutrients are generally preferred, though ultra-low nutrient systems can cause issues. Alkalinity stability is paramount— even small swings can cause tissue loss. Many successful Acropora keepers dose trace elements and use high-quality salt mixes.

Feeding Biology & Symbiosis

Acropora rely heavily on their zooxanthellae for nutrition but also capture fine particulate matter and bacterioplankton. Their small polyps are not suited for large food items like other corals.

• Phytoplankton and bacterioplankton
• Amino acid supplements
• Coral-specific foods with fine particle sizes
• Dissolved organic compounds

Broadcast feeding of fine foods and amino acid dosing can enhance growth and coloration. Many hobbyists find that diverse fish populations provide adequate feeding through waste products.

Common Diseases, Pests & Predators

• Acropora Eating Flatworms (AEFW) – devastating and difficult to detect
• Red Bugs (Tegastes acroporanus) – tiny parasitic copepods
• Rapid Tissue Necrosis (RTN) – fast-spreading tissue death
• Slow Tissue Necrosis (STN) – gradual tissue recession
• Montipora Eating Nudibranchs (can affect Acropora too)

Quarantine and dipping all new Acropora is absolutely essential. Regular inspection for pests should be routine. RTN and STN often result from parameter instability or sudden environmental changes.

Compatibility & Placement

Acropora are relatively peaceful corals with limited stinging capability compared to LPS corals. However, they can be damaged by more aggressive neighbors. Inter-species aggression between touching Acropora colonies can occur.

• Best zone: Upper tank with intense light and flow
• Give space: 2–3 inches minimum for growth
• Keep away from: Aggressive LPS, leather corals, anemones

Fragging Techniques

Acropora frag easily using bone cutters or coral saws. Branch tips make ideal frags as they contain the fast-growing axial corallite. Frags can be glued to plugs or directly to rock. Healing is typically rapid under good conditions. Many hobbyists build impressive collections through fragging and trading.

Aquacultured Strains & Trade Names

Thousands of named Acropora varieties exist: "Oregon Tort," "Walt Disney," "Strawberry Shortcake," "Homewrecker," "Miyagi Tort," and countless others. Most are aquacultured and significantly hardier than wild specimens. Popular species include A. tenuis, A. millepora, A. tortuosa, A. valida, and A. nasuta.

Difficulty Rating & Summary

Difficulty: Advanced

Acropora represent the ultimate challenge and reward in reef keeping. Their demanding requirements for stable chemistry, intense light, and strong flow mean they're best suited for experienced aquarists with mature, well-maintained systems. Success with Acropora is considered a milestone achievement in the hobby.