Acan Corals

What are acan corals?

Acan corals are fleshy large polyp stony corals that grow as low, spreading mats of tightly packed polyps, each ringed with concentric bands of color. Nearly every coral sold as an acan lord today is Micromussa lordhowensis, reclassified from Acanthastrea lordhowensis in 2016. They are among the most collectible LPS corals because a single colony can carry several contrasting colors in one polyp.

Acan coral care: light, flow, and feeding

Acans want less of almost everything than new reefers expect. Low to moderate light suits them, and gentle, indirect flow keeps the tissue fully inflated without stripping it back. Check your reef lighting before placing a frag high in the tank, and keep alkalinity and calcium steady with dependable water testing equipment. The single biggest lever on growth and color is food: target feed once or twice a week after the tentacles emerge, and keep portions small enough that nothing settles uneaten.

Acan lords, echinatas, and rainbow morphs

Collectors sort acans mostly by color pattern rather than species:

• Micromussa lordhowensis — the classic acan lord, with round, tightly packed polyps and banded centers. Rainbow, bleeding apple, and master morphs all come from this group.
• Acanthastrea echinata — larger, more widely spaced polyps on a heavier skeleton. Often sold simply as echinata, and slightly more forgiving of stronger light.
• Rainbow and multicolor morphs — named lineages selected for three or more distinct colors in a single polyp. These carry a premium and generally hold color best under moderate, stable lighting rather than maximum intensity.

Placement and aggression in a mixed reef

Acans are peaceful by day and considerably less so at night, when they push out feeding tentacles that can burn a neighboring coral. Leave three to four inches of open space around each colony, and be especially careful downstream of chalices, torches, and other species with long sweepers, which easily out-reach an acan. Because they prefer the calmer, dimmer parts of the tank, the sand bed and lower rock shelves are usually the right home, and that placement also keeps them clear of high-light SPS.

Building an acan garden

Acans look best massed together, where contrasting morphs read as a single mosaic. Start with two or three frags on the same shelf and let them grow into each other rather than scattering them around the tank. Browse the full range of live corals for sale, pair them with forgiving tankmates from our beginner corals selection, or compare value options under fifty dollars in corals under $50.