Acan Coral


Acan corals are becoming a must for every reef keeper’s tank. The bright striped color combinations these corals exhibit along with being a hardy coral is just too good to pass up. The decent growth rate and ability to propagate this coral has led to its explosion onto the reef keeping scene over the last few years.


Common Names:  Acan Coral, Acanthastrea Coral

Skill Level: Beginner

Classification: LPS

Disposition:  Aggressive

Light Level: Moderate

Water Flow: Moderate

Water Conditions: 72-78° F, dKH 8-12, pH 8.1-8.4, sg 1.023-1.025



The different color patterns you can find Acan corals in are probably the most extensive of all the corals available in reef keeping. Here are a just a few colors of the variety you can find Acans in.

Blue and Red Acan

Purple and Green Acan
Purple and Green Acan

Red and Blue Acan
Red with Blue Acan

Purple blue and green acan
Purple Blue Green Acan

Red Orange Purple Acan
Red Orange Purple Acan


The disposition of the Acan coral is considered aggressive, it is important to know that the coral should be placed so that no other corals are within a few inches of it. While I have never seen an Acan do this they have been known to extend their stomachs out onto neighboring corals to attack them.


Acanthastrea corals do contain zooxanthellae within their bodies to provide for some of their nutritional requirements through photosynthesis. This basically means that they have the ability to get some of their food from the lights on your tank. However for a much faster growing and happier coral it is recommended that you feed this coral every few days. I feed my Acans every two days and have seen great growth. I take raw shrimp bought from the grocery store and blend it up into very small pieces. Then I suck it up in a turkey baster and shoot the small pieces onto the Acan. The coral catches the small pieces of food in their tentacles and draws it into their mouth. I have read many places that it is suggested to feed your Acans at night but I have found this is not necessary. In most cases my corals will eat the food no matter what time of day it is. I have however noticed that it is easier to feed the fish first, then the corals second. The coral will sense the food in the water and you can see the tentacles begin to extend. When the tentacles are out feel free to feed the Acans. If your Acan colony is new to your tank you can expect the Acan to not eat for several weeks, this is acceptable. Once it is settled in you will notice when it’s ready to begin feeding. The image below displays an Acan Coral with its tentacles extended and ready to eat for reference.

In the image below I fed the acan polyps a minute apart to show the different phases of Acan coral ingestion.
Step one: In the Green Circle the polyp has caught its food and is drawing it toward its mouth.
Step two: In the White Circle the polyp closes around its food and pulls it into its mouth.
Step three: The yellow circle shows the food has been fully ingested.

Acan eating phases


When it comes to lighting there is such a thing as too much light. Make sure to not bake your Acan colony. If the coral is getting too much light you will notice they stay closed up. Moderate light is plenty; too much light can be deadly to your coral. Moderate flow is best as well. When placing the coral it is also important to realize that placed on rock, tank bottom, or sand bed does matter. I would recommend not placing the coral on the sand bottom. I have heard from fellow reefers that sand can get between the polyp and the skeleton and eventually cause the polyp to die. I have never seen this personally but have heard about it a few times. If you choose to place the coral on a bare tank bottom you can expect the coral to grow into a ball shape. This is due to the fact that corals will grow around the skeleton they formed in the middle. This can produce a very neat looking show piece coral but it does hinder the growth rate. To me the ideal placement of the coral is mounted to a rock so that it can have the maximum growth potential and the most natural look.

Acan Coral Placement
Acan Coral Placement


Propagation of this coral is more difficult than most other corals. The ideal propagation technique is with a band saw. This way you can move the coral through the saw trying to damage the polyps the least amount as possible. However if you do happen to cut one in most cases it will heal up just fine, or often will cause the polyp to split and create another Acan coral. The reason a band saw is needed is that in most cases the corals will encrust over a rock creating less skeleton than if it was left to grow on a tank bottom or sand bottom. Since you can seriously damage the coral by ripping it off the rock most people choose to cut through the rock as well. The 2nd choice for propagation tool would be a Dremel, the act is the same but it’s harder to use.

More Information: Acan Coral

39 thoughts on “Acan Coral

  1. Hi…this info is exactly what I hoped to receive as a beginner. using Acans. I have a very large aquarium (8′ X 4′ X 2′) that is 20 years in the making. I allowed all my fish to expire normally and now the tank seems pristeen for growing corals. However, is 3 feet deep too deep ? (1 foot is deep, old substate of sand & gravel), yet moderate light gets there? Thanks…an appreciate your info…Phil

    1. Hi Phil,
      So the distance from your lights to your corals is probably around 3 foot still? I’m just guessing your lights are 12 inches or so above your tank and your Acans are in 2 foot of water since 1 foot is sand bed?
      If your getting moderate light then i think that sounds about perfect. I almost always place my Acans near the bottom of tanks i setup. My personal acans are currently only getting moderate light and are very happy and are growing great. Thanks for the comment an thanks for reading, hope i answered your question!

      1. I recently purchased 2 acans. I have 4 zoomed t5s 1″ above the tank. the tank is 20″ deep. I have the acans on the bottom currently. they open up nicely at night and feed but during the day, they stay shut completely. can you tell me what i must do to get them to open during the day?

        1. Hi Kirk,
          This sounds like the acans are not handling being under your lights very well yet. i would suggest putting one or two screens beween your lights and the tank or raising your t5s a little bit until you notice the acans open during the day. After a week remove the screen or lower the light a little bit and see if the acans can handle the light. I wouldnt worry about killing them, this happens to me pretty often when creating acan frags and moving them to different tanks under different lights.
          Good luck with the acans and let me know how it goes!

  2. Hi there, i purchased my first acan on saturday, the polyps seem open but with no tentecles… have moved to a shaded area of tank now… any help appreciated.

    1. Hi Dan,
      Sorry It took so long to respond to this. I didn’t realize I had missed your comment.
      If the polyp is open that’s a good sign especially for a newly bought acan. Have you tried looking at the coral in the dark with a flashlight to see if it’s extending its tentacles then?
      It’s also entirely possible it is just not trying to feed at that current time since it was new to your tank.
      How is the coral doing now?

  3. Hi
    I just want to say I have learnt more in 2 minutes reading your site than I have reading books and endless forum talk.
    Great to have some one who knows
    thanks Jim

  4. Hi,I love your site!its very question is I have multiple corals, lps sps mushrooms ricordias anemones and some fish.I am currently running an AI sol with white blue and royal blue and I’ve read that a lot of corals need the red would I go about switching to my halid and t-5s or would you stay with the AI sol?

    1. Hi Cody,
      Thanks for the comment. I wouldn’t specifically say that you “need” to have any light in the red spectrum. I have seen tanks that specifically have it and it does make some of the reds and purples feel more vibrant. If you were to switch to T5’s you could substitute in a bulb such as the Fiji purple instead of a blue actinic. I do have two chinese LED sets which i ordered to have a few Red bulbs swapped in from some of the white spectrum and I personally have never seen anything that has pointed to the coral benefiting health wise from this spectrum of light. If your corals are healthy under your current LED setup I believe you would run a larger risk changing your current light settings than adding a red spectrum.
      Hope this helps!

  5. I have also noticed that my acans cycle once or twice a day going from shrunk up to fully extended. It appears to be an entirely normal part of their daily life. Mine are eating whenever food is offered, growing amazingly fast. Coloring up more each week and generally thriving. Mine are under LED lighting at about 150 par at noon. I have a meter but my lights are run on a natural sun intensity curve so the lights are only at thier brightest for a few hours in the middle of the day. The morning and evening are ramping up to and down from the high setting. 12 hour total cycle.

  6. Great site for beginner coral keepers. Thanks so much for doing it. I’ve had a two head acan colony for the last 3-4 weeks. One head has had about half of it disintegrate for lack of a better word and the other about a quarter disintegrated. Calcium, Magnesium, Phosphate, Nitrates, pH, Alk and salinity are within the above parameters. Any idea what may be causing this? Thanks in advance

    1. I have noticed that acans are very sensative to alk swings and I have had mine disintergrate as well before when purchasing acans with an alk diff that is more than 2-3.

  7. I understand that acans can be dangerous around other corals, but can different acans be placed near each other? Almost like an acan garden in one corner of the tank. I would like to place different colored frags near each other. Thanks for your help.

    1. Hello,
      I keep my acans next to each other without any I’ll effects other than I do feel that if they are too close it can hinder their growth. Thanks for posting!

  8. Hi Tom, Great site for newbies like me 🙂 I’m trying to plan spacing on my reef. How large will these Acans get? Should I leave at least 6″ and my xenia or zoas?

    1. Hello,
      I Acans will grow as large as you will let them since they will grow outwards almost like a mat.
      I would leave at least 6 inches from your xenia or zoas especially because both of those will probably outpace your acans by a lot.

  9. I am currently looking to purchase an acan. I want something that is good in color (bright pinks/oranges/purples). Can you suggest any and where to purchase? I really don’t want to spend a mint at this time as I am very new to this. Any help would be great. Thanks

  10. my acons were doing great until a large “fuzzy” style mushroom was touching it… now the botfomxones on the colony are bleached out. I moved them to another rock but the other heads arexnot opening up very well… what do i do; dont want to loose the whole colony.

    1. Hi,
      Are the acans currently just closed or do you see actual die off? If they are just closed and mad I wouldn’t do anything if the stung corals appear to be melting I would frag those pieces off.

  11. I have 2 tanks , the small tank the acan is too good and the big tank the acan doesnt open , t5 ,low flow , good place in the pottom in both tanks, please can u help me

  12. I bought 2 Acans yesterday one that is red and pink and another that was blue and green. It has been a day and both Acans look great, but the one that was blue and green is currently pink and green. What may be wrong with my Acan? How can I get the color back?

    1. There may not be a problem at all especially if you noticed the color difference right away. I would assume that you have different lighting and the color spectrum is different making your acan appear a different color.

  13. hi i bought 2 acans a week apart and they have never opened this was at least 2 months olook a little worse than the other but they are still alive…alll my parameters are perfect or close except for my iodine which i have been slowley raising….i have moved them to every possible location. and waited for more posative results…….my confusion is that i have a 500 gallon tank containing almost every other species of coral….all are doing fantastic except for acans..i gave them a coral dip today and i am awaiting the results…i did see some very small white centapede lookin things come out, or off of this coral..i also have try to stimulate them by feeding but to no least the one still has zooanthale within that i can see under my actinic led lights, any info will be greatley appreciated ..thanx jim

    1. Hi Jim,
      Sorry to hear about your acan problems, did you start them low in the tank when youf irst got them?
      Im wondering if they were baked under your lights compared to the lighting they were in .

  14. This is a great read. Thank for putting this together. I have been keeping Acans for about 7 months. Up until about two-weeks ago they were thriving. Two weeks ago all of my acans closed down. I did not make any changes to the tank. The water parameters are stable and have not changed during that time.

    Any thoughts on why this happened?

  15. I have an acan colony that was doing very well until the neighboring mushroom colony took off. Now there is a mushroom right up on it and that area is dying off at a pretty quick rate. I tried to move the colony, but it is attached to the rock. Can it just be sawed off of the rock, or would that cause irreparable damage? I’d be willing to sacrifice that one mushroom, but I suspect another will just take up residence there. Any advice would be appreciated, Great article, by the way.

    1. The Acans can be sawed off the rock but it’s pretty risky. Some will survive but it’s very hard on the corals and you will probably have a lot of die off.

  16. Hi how long can it take a new rainbow Acans to a simulate to a new tank. The place I bought said place in low light. Is this correct? Thanks

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