Acan Coral Care Guide (Micromussa lordhowensis)

Introduction

Acan corals (Micromussa lordhowensis), commonly called Acan Lords or Acanthastrea corals, are among the most vibrant and popular large polyp stony (LPS) corals in the reef aquarium hobby. Their fleshy polyps and striking colors make them a standout addition to any reef tank. Acans are relatively hardy, adapt well to moderate lighting and gentle water flow, and respond positively to occasional target feeding. Whether you are a beginner or an experienced aquarist, following the right care practices will ensure your Acans thrive and maintain their stunning coloration.

Scientific Name Controversy

Historically, these corals were sold as Acanthastrea lordhowensis. In 2016, taxonomists reclassified them as Micromussa lordhowensis. Despite the update, the common shorthand “Acan” remains widely used in the aquarium trade, which can sometimes cause confusion. Both names refer to the same coral species prized by reef hobbyists.

Natural Habitat

Acans are native to the Indo-Pacific, particularly around the Great Barrier Reef, Lord Howe Island, and other coral-rich lagoons. They thrive on sandy substrates and lower reef slopes where light levels are moderate and water movement is gentle. Replicating these natural conditions in your home aquarium is key to promoting healthy growth and vibrant coloration.

Aquarium Care & Setup

Temperature: 74–80°F (23–27°C)

pH: 8.1–8.4

Salinity: 1.024–1.026

Flow: Low to moderate; avoid strong direct flow that prevents full polyp extension

Lighting: Moderate, ideally 50–150 PAR. Excessive light can cause bleaching, while insufficient light may dull coloration.

Placement: Acans thrive on the sandbed or lower rockwork. 

Feeding Acan Corals

Although Acans are photosynthetic, they benefit from supplemental feeding. At night, their polyps extend feeder tentacles that accept small meaty foods such as mysis shrimp, brine shrimp, or coral-specific pellets. Feeding 2–3 times per week encourages faster growth, vibrant colors, and full polyp expansion.

Growth and Behavior

Acans grow outward in an encrusting pattern, producing large, fleshy polyps. Polyps expand during the day and extend feeding tentacles at night, making them visually appealing at all times.

Tankmates

Acans are compatible with most peaceful reef-safe fish and invertebrates. Avoid aggressive species that may pick at the polyps. Suitable tankmates include tangs, gobies, cleaner shrimp, and snails.