Acan Coral Care Guide (Acanthastrea)
Acan corals — short for Acanthastrea (and the closely related Micromussa) — are among the most collected LPS corals in the hobby. Their fleshy, jewel-toned polyps come in electric greens, reds, oranges, and rainbow combinations, and they grow into tight, colorful colonies that are easy to frag and trade. Acans are hardy, forgiving, and fantastic feeders, making them a top pick for beginners and collectors alike. This guide covers lighting, flow, placement, parameters, feeding, aggression, and acclimation.
Care Level: Beginner-Friendly
Acans are hardy and adaptable, asking mainly for gentle flow, moderate light, and stable water. They’re heavy feeders that reward you with fast growth and deeper color when fed regularly.
Quick-Reference Care Parameters
| Coral type | LPS (Large Polyp Stony) |
| Care level | Beginner–Intermediate |
| Lighting | Low–Moderate · PAR 50–120 |
| Flow | Low–Moderate, gentle and indirect |
| Placement | Sandbed or low rock (bottom third) |
| Temperature | 76–82°F (ideal ~78°F) |
| Salinity | 1.024–1.026 (~35 ppt) |
| Alkalinity | 8–11 dKH |
| Calcium | 400–450 ppm |
| Magnesium | 1250–1350 ppm |
| Nitrate | 2–10 ppm |
| Phosphate | 0.03–0.10 ppm |
| Feeding | Highly beneficial · meaty foods 1–2× per week |
| Aggression | Mild–moderate · short sweeper tentacles |
Lighting
Acans color up best under low-to-moderate light (PAR 50–120). Too much light washes out their color or bleaches the tissue; too little dulls them. A blue-heavy spectrum makes their fluorescent pigments glow. Placed lower in the tank and acclimated gradually to your lighting, they hold rich, saturated color.
Water Flow
Give acans gentle, indirect flow. Enough to keep detritus off the polyps, but not a direct stream — strong flow keeps the fleshy polyps from inflating fully and can irritate them. Random, moderate movement is ideal.
Placement
Place acans on the sandbed or low rockwork in the bottom third of the tank where light and flow are moderate. They encrust and spread across their base over time, so leave a little room around the colony.
Water Parameters
As a stony coral, acans want stable alkalinity (8–11 dKH), calcium (400–450 ppm), and magnesium (1250–1350 ppm), with steady temperature and salinity. Consistency matters more than chasing a specific number. A little nutrient in the water (nitrate 2–10 ppm, phosphate 0.03–0.10 ppm) helps them stay plump and colorful.
Feeding
Acans are among the best-feeding corals you can keep, and feeding is the single biggest driver of growth and color. After dark — or whenever their feeder tentacles emerge — target-feed small meaty foods (mysis, chopped shrimp, or a coral food) one to two times a week. Feed in reduced flow so the food settles onto the polyps.
Aggression
Acans have relatively short sweeper tentacles and are only mildly-to-moderately aggressive, but they will sting corals they’re touching. Give a couple of inches of space between an acan colony and its neighbors.
Common Problems
- Not inflating: usually too much flow or light, or new-coral stress. Move it lower and calmer and give it time.
- Faded color: often too much light or an unstable tank; lower the light and steady your parameters.
- Recession between polyps: a stress signal — check for parameter swings or a stinging neighbor.
How to Acclimate Your New Acan Coral
- Temperature match (15–20 min): Float the sealed bag with lights dimmed to equalize temperature.
- Drip acclimate (30–45 min): Open into a clean container and drip tank water in slowly until the volume roughly doubles.
- Coral dip (5–10 min): Use a reef-safe dip per directions, then rinse in clean saltwater.
- Placement: Set the frag low, in gentle flow and moderate light, clear of other corals.
- Let it settle: A new acan may look deflated for a few days — that’s normal. Once settled, a light feeding helps it plump up and color in.
Frequently Asked Questions
Are acan corals good for beginners?
Yes — they’re hardy, colorful, easy to feed, and simple to frag, making them a great early LPS.
Why isn’t my acan puffing up?
Usually the flow is too strong or the light too intense, or it’s still settling in. Move it lower and calmer and be patient.
How do I get better color on my acans?
Moderate blue-heavy light, stable water, and regular feeding are the three levers. Feeding especially deepens color over time.
What is WYSIWYG coral?
WYSIWYG means “What You See Is What You Get” — the exact coral pictured is the one shipped to you.
Shop WYSIWYG Acan Coral & Care Guides
Browse our live coral for sale for this week’s hand-selected WYSIWYG acans. See more in our library, including the Cynarina Care Guide, the Lobophyllia Care Guide, and the Chalice Care Guide.
