Rainbow Lord Acan Coral | S#003 | WYSIWYG

Placement, Lighting & Flow

Rainbow Lord Acan (Micromussa lordhowensis) performs best under low to moderate lighting. A PAR range of approximately 50–150 is suitable for most specimens, with the sandbed or lower rockwork usually providing an ideal starting position.

These corals can be particularly responsive to changes in lighting, and both colour and polyp expansion may change when a specimen is moved between systems. Avoid placing a newly introduced Lord Acan directly under intense reef lighting. Begin in a lower-light position and increase exposure gradually if required.

Provide low to moderate, indirect water movement. Flow should be sufficient to prevent detritus settling between the polyps while allowing the fleshy tissue to inflate naturally. Strong direct flow can prevent full expansion and may cause the delicate tissue to rub against or pull away from the skeleton.

Feeding & Nutrition

Lord Acans are photosynthetic and obtain a substantial proportion of their energy from their symbiotic algae, but they are also enthusiastic feeders. Supplemental feeding is beneficial and can support stronger growth, polyp condition and colouration.

Small portions can be target fed approximately once or twice per week. Suitable foods include mysis shrimp, enriched brine shrimp, finely chopped marine foods and appropriately sized LPS coral pellets. Each polyp is capable of capturing food, so offer small pieces rather than placing a large amount onto the colony.

Feeding is often easiest when the feeding tentacles are extended. Temporarily reducing water movement can give the coral time to capture food before it is carried away. Avoid excessive feeding, as uneaten food can become trapped between the polyps and contribute to deteriorating water quality.

Compatibility & Spacing

Lord Acans are moderately aggressive. Their feeding and short sweeper tentacles can sting neighbouring corals, particularly after dark, so allow several centimetres of clear space around the colony and additional room for future growth.

Do not assume that all corals commonly sold as “Acans” are safe to place together. The aquarium trade name covers corals from different genera, and true Acanthastrea species can be substantially more aggressive than Micromussa lordhowensis. Avoid direct tissue contact unless compatibility between the particular colonies is known.

Lord Acans generally work well in mixed reef aquariums when given their own space. Keep them away from strongly aggressive LPS corals with long sweeper tentacles and from fish or invertebrates that repeatedly pick at their fleshy tissue.

Growth & Behaviour

Micromussa lordhowensis forms compact colonies of fleshy individual polyps over a stony skeleton. New polyps typically develop around the perimeter of the colony, gradually creating a larger rounded or mounding group.

Growth is generally slow to moderate and can improve noticeably with stable conditions and occasional feeding. Healthy polyps should appear full and fleshy when expanded, although the amount of inflation can change during the day and in response to feeding, lighting and water movement.

Feeding tentacles are often most obvious during the evening or after food enters the water, although established specimens may learn to extend readily during daytime feeding.

Acclimation & Introduction

After transport, give the coral time to settle in a lower-light area with gentle to moderate water movement. Avoid immediately placing a newly arrived specimen in the brightest part of the aquarium, even if its intended permanent position receives stronger light.

Inspect the coral carefully before introduction, paying particular attention to the underside, exposed skeleton and spaces between polyps. Look for damaged tissue, unwanted algae, pests or areas of recession. A suitable coral dip and a period of separate observation or quarantine can reduce the risk of introducing unwanted organisms into the display aquarium.

Once the coral has settled and is showing consistent expansion, it can be moved gradually if a different final position is required. Avoid repeatedly relocating a healthy specimen once it has adapted to a suitable location.

Common Problems & Prevention

The large fleshy polyps of Lord Acans can be damaged by excessive flow, abrasion against rockwork, neighbouring corals or rough handling. Tissue damage can expose the underlying skeleton and create an opportunity for further recession or infection.

Excessive lighting may cause paling, bleaching or poor expansion, while insufficient water movement can allow detritus to accumulate between the polyps. Keep the colony clean without directing a harsh jet of water at the tissue.

Algae growing onto exposed skeletal areas can interfere with recovering tissue, so declining colonies should be investigated promptly. Stable aquarium conditions, careful placement, appropriate flow and avoiding physical injury provide the best defence against most problems.

Signs of Stress

A newly transported Lord Acan may remain partially contracted while adjusting to its new environment. Persistent deflation, significant colour loss, bleaching, receding tissue, exposed skeleton or polyps that remain tightly withdrawn for several days warrant closer investigation.

Check lighting and flow first, followed by temperature, salinity and general water stability. Avoid making several major changes simultaneously; identifying and correcting the underlying cause while maintaining stable conditions is preferable to repeatedly moving or adjusting the coral.

Handling & Fragging

Handle the coral by its frag plug or exposed skeleton whenever possible rather than touching the fleshy polyps. The inflated tissue extends well beyond the skeleton and can be easily torn or compressed.

Established colonies can be propagated by cutting through the skeleton between individual polyps. A clean coral saw provides considerably better control than breaking the colony by hand. Avoid cutting through living polyp tissue wherever possible and allow newly fragged sections time to recover in clean water with gentle to moderate flow.

Wear gloves and eye protection when handling or fragging corals, and use clean equipment to reduce the risk of transferring contaminants or pathogens between colonies.

Who Is This Coral Best Suited For?

Rainbow Lord Acan is an excellent choice for reef keepers looking for a colourful, relatively forgiving LPS coral for the lower areas of an established aquarium. Its compact growth, strong feeding response and extraordinary variation in colour make it particularly well suited to mixed reefs and dedicated LPS displays.