Acan Coral Care Guide

Acan Coral is photosynthetic and can survive on light and dissolved nutrients, but target feeding significantly improves growth rate, polyp size, and color intensity. Acans respond best to meaty foods like mysis shrimp, brine shrimp, reef roids, and coral pellets offered two to three times per week.

Feeding after lights dim, typically one to two hours after lights-out, produces the strongest response as polyps naturally extend feeding tentacles at night. The polyps actively grab food placed directly on the oral disc, making target feeding straightforward. Mysis shrimp provides fatty acids that can intensify reds and oranges, while pellet foods deliver amino acids that support tissue growth.

Acan Coral is semi-aggressive and extends short sweeper tentacles approximately 1-2 inches at night to defend territory and capture food. Acans can also deploy mesenterial filaments — digestive tissues capable of damaging or killing neighboring corals placed within a couple of inches.

Reef keepers should maintain at least 4-6 inches of spacing between Acans and other corals to prevent stinging and digestive damage. Acans are less aggressive than Euphyllia species like torch and hammer corals but can still damage soft corals like zoanthids if placed too close. Planning for colony growth when spacing is important, as colonies expand outward over time.

Acan Coral color loss is most commonly caused by excessive lighting, as Acans prefer low to moderate PAR levels and bleach under intense light. Colonies placed too high in the tank or under recently upgraded lighting fixtures often fade on the upper surfaces first before losing color across the entire colony.

Insufficient nutrients can also cause color loss, as Acans thrive in systems with nitrate levels around 5-10 ppm and phosphate around 0.05-0.1 ppm. Ultra-low nutrient systems that work well for SPS corals can cause gradual paling over months. Reef keepers noticing fading should reduce lighting, increase feeding frequency, and verify nutrient levels are not too low.

Acan Coral is considered a beginner to intermediate LPS coral due to its hardiness and adaptability across a range of tank conditions. Acans do not require intense lighting, tolerate moderate parameter fluctuations, and grow steadily with minimal intervention.

The semi-aggressive nature requires some awareness of spacing and coral compatibility, which may be less intuitive for brand-new reef keepers. Stable water parameters and occasional target feeding are sufficient for vibrant colors even in newer reef tanks, making Acans an excellent early LPS choice after establishing basic water chemistry management.

Acan Coral can retract polyps and remain closed due to several common stressors in the aquarium environment. Excessive or direct water flow is a frequent cause of retraction, as strong current prevents polyps from fully inflating and interferes with feeding. Lighting that is too intense, particularly after upgrading fixtures or moving the coral higher in the tank, also causes polyps to stay retracted at peak intensity.

Reef keepers should check for aggression from neighboring corals with sweeper tentacles, fish nipping from species like flame angelfish, and heavy metal contamination in the water. Maintaining stable parameters and placing Acans in a lower-light, indirect-flow location typically resolves retraction within a few days.

Acan Lord (Micromussa lordhowensis, formerly Acanthastrea lordhowensis) and Acan Echinata (Acanthastrea echinata) are commonly sold under the shared name "Acan" but belong to different genera following a 2016 taxonomic reclassification based on molecular DNA analysis. Acan Lord polyps are smaller and pack more densely together with a finely beaded skeletal texture, while Acan Echinata polyps are larger with wider spacing and a more spiked skeletal structure.

Acan Lord colonies tend to be more aggressive feeders and may require slightly lower lighting than Acan Echinata. Both corals share similar care requirements overall, but reef keepers should note that online vendors may still use the outdated Acanthastrea lordhowensis name when listing Acan Lord specimens.