Acanthastrea lordhowensis color change


New member
Mine has gone from red and green to white and pink in the course of two weeks. I am concerned that it's dying, but it has maintained its original overall size, it eats bioplankton and cyclop-eeze well and on top of that, I see new polyps growing out from the original piece. Can anybody tell me what's going on?


Limestone Cowboy.
Premium Member
Could be getting too much light. Where at in your tank and what lighting do ya use?


New member
<img src="/images/welcome.gif" width="500" height="62"><br><b><i><big><big>To Reef Central, Kimbo</b></i></big></big>

It sounds like it is bleaching; losing its zoox density. This is a stress response and can be caused by anything from intense lighting to temperature fluctuation. The feedings are helping it tremendously right now. I would definitely continue to feed it. Check your water for any fluctuating parameters, and check out your temperature specifically because of the summer heat.

For now the best things to do are:

1. Keep feeding it
2. Check your water
3. Provide us with more information about your aquarium (lighting, parameters, coral placement, etc.) (Placement in tank will be important as this could be the result of too much light)

Good luck :thumbsup:


New member
Thanx guys for the info.

My tank is a 24 gallon Aquapod nano


1-32W square pin Dual Daylight 10000¡Ã" K/6700¡Ã" K Daylight bulb, 1-32W square pin Dual Actinic 460nm/420nm Actinic bulb, 2 blue LED lights

Lighting schedule:
1) 1 hour actinic
2) 5-6 hours actinic + daylight
3) 1 hour actinic
4) lights off

I have placed the coral smack in the middle in terms of height, in an area of moderate flow.

I just got my water tested, and everything checks out fine, including calcium levels.

In terms of temp, aside from transient fluctuations during water changes, the tank has not experienced any major temp issues.

If the coral isn't doing so hot, how is it that it's still proliferating?



New member
Have you tested your temperature recently? Do you know what it is specifically?

The placement sounds fine for the coral. You could move it down a little to be safe, but I don't think it is necessary.

This is a stress response from the coral most likely caused by some kind of abiotic factor in your aquarium. The color loss you are noticing is the result of the coral expelling its zooxanthellae. This is a symbiotic algae living within the coral tissue. Because it is not part of the coral itself, it can be expelled as the coral continues to feed and extend. :)


New member
Jared, can the coral make a "comeback?" I just digitally checked my temp, and it is at exactly 77 degrees F. I keep my air conditioner on in my apt almost 24/7 (the benefits of it being included in the rent), so there is no danger of overheating. Thanx for all the help.


New member
Yes, it will just require good, stable water conditions and supplement feedings.

Something has happened in the two week period to stress it enough to cause it to expel its zoox. It could have even been something brief but drastic. For now, I would just continue to feed it, maybe slowly move it lower in the tank, monitor your parameters, and make sure there are no nearby competitors.

Keep us updated with progress or questions, good luck :thumbsup:


New member
well, from the way you responded it sounds like you dont have your own kits and had your water tested at an lfs or something. first id suggest getting your own test kits. not trying to lecture but they should be one of your first purchases when entering this hobby. also i wonder what was tested exactly and what the exact readings on those were.
i can only think of two things that would suddenly cause this. lights and params. i dont think your lights are whats doing it, especially since its half way down the tank. so that almost has to point to your params.
post some numbers if you can and we'll try to help you figure this out.


Premium Member
All the color changes my corals have gone through is due to the fact that I used different lights than the place I got them from. And, of course, the distance to the light.


New member
Kimbo didn't say it had lost its zooxanthellae because they didn't know what was happening. (hence the creation of this thread)

A change in color, such as a brown coral "coloring up" to blue or a green coral getting even brighter can be attributed to a change in water conditions and lighting. (To generalize for this case)

When a coral changes from a solid color to a lighter/transparent version of the color (sometimes even white) it is attributed to the expulsion of zooxanthellae, the symbiotic dinoflagellate that resides within the coral acting out the process of photosynthesis. This act has become known as "bleaching" because the coral begins to change from its original color to a lighter version until it reaches the extreme of becoming white/transparent. (Appearing as though it has been bleached) It is a stress response usually the result of an irritating abiotic factor. I am guessing that in the case of Kimbo's coral, the area that is now white used to be green, and the area that is now pink is the lighter version of what used to be red. This is because the coral has bleached.

In Kimbo's case this irritating, abiotic factor could be anything from light to temperature. In my case, the factor is biotic.

Good luck, Kimbo :thumbsup:


New member
My water parameters using my own test kits:

Ammonia: 0
Nitrite: 0
Nitrate: 0
pH: 8.2
Calcium: 440 ppm
Alkalinity: 12 dKH


New member
alk seems a little high. Natural seawater is around 8 dKH. I would let that drop some (over time of course).


In Memoriam
can we get a pic?from what i know of acans they can return (almost)from the dead.ive seen some really sad bleaching rtned colonys come back to really nice corals!how often are you doing water changes on the tank?

Me No Nemo

Premium Member
I had several come into my shop that changed from red/green to a white/green over the first week. I moved them into a dimly lit area and they came back very well. Many of these corals are kept in sub standard lighting from the time they are harvested until they reach your tank...the lighting also is often different from collector to wholesaler to LFS to you. Most tanks they finally settle into have a much higher light value than most of the others in the chain of custody. The intense lighting in our tanks is often a shock. I would suggest a low light area until it begins to color back up, and feed well. GL, HTH, Marcye