Coral color changed from Green to Yellow on this Bird Nest... Or is bleaching ?

[Danreef]

Hi All

I was going to wait some more days to post this. But in lieu of an excellent discussion we have today on this thread ( http://www.reefsanctuary.com/forums...s-definition-what-low-high-nutrient-tank.html ) that finished in some comments on coral color, I decided to do the posting.

Going to the point. In the last weeks (~3 weeks) I started to notice a slight change of this bird nest, from its classical green color to this yellow color.

At the beginning I started to think on bleaching. But I discarded that because when this coral was in my Nano tank at less than 4-5 inches of the LEDs that where at 70% I did not see any change in color (a picture can be seen in the first posting of my thread here :http://www.reefsanctuary.com/forums...niels-tank-upgrade-rsm-250-a.html#post1251540 , the coral is the one on the medium/left over the rock).

Since I moved it to the new tank (RSM250 of the thread) it has been healthy and growing. Still is growing, just the color change is picking my attention.

Not that I dislike the new color, It is very pretty, but I would like to share it and see if anyone would like to comment.

Some tank data:

RSM 250 all standard with the exception of a refugium on the media rack.

- Lights : Red Sea T5 Spec PLUS one 36" TrueLumen Pro actinic LED strip + one 36" Ecoxotic Actinic/Purple LED strip + one 24" Trulumen Pro actinic LED strip
- Water: Petco Natural Ocean Water
- Dosing: Ca and Alk
- PO4: 0.18-0.16 ppm
-Ca: 417 ppm
- Alk: 10 dKh
- Mg: Lats time I measured it (1 month ago) was on the classical range. Because it is always like that I do measure it very sporadically.
-Water Changes: ~10-15% every week.

Here is the picture. The upper picture is from today and the other is from around ~3 months (Grrr photobucket do not keep the date of the upload. I estimate it due to his growth and the coral growth around him - see picture and you will notice the growth-).



This is today's full picture




Any comments ?
What do you think ?
Could be that is really bleaching ?




Thanks
Daniel

 

[Lexinverts]

If that is an ORA neon green birdsnest, then I would say that it is bleaching. I have a bunch of those, and they all look like the first picture.

 

[Oxylebius]

If it is a Seriatopora hystrix, they can change from greenish to yellow and some even come is a variety of pinks.

If it is bleaching, you have several options:

1) Re-examine your lighting schedule. How long ago was it when you made any changes to your lighting (bulb replacement or timing change or additional lighting added, etc.). Sometimes it can take a couple of weeks to start to affect corals. Since the coral is slowly turning green to yellow, it could be slowly adjusting to the lighting, or slowly bleaching. Not all bleaching happens fast. What to do? Diminish lighting or timing the lights are on for.

2) One item you didn't list was the temperature of the tank. What do you usually have it at. Was there any fluctuations where the temp rose?

3) You can consider moving the coral lower in the water column. You can save all of it or frag it to save some of it. It is a good sized coral, so I'm not sure if you can get under it and make a clean break in the base, but fragging some part of it is also an option.

 

[Danreef]

Tank Temperature 79-80 F since the set-up of the tank.

It could be the lights. This morning I woke up remembering that this coral did the same at his start. Yesterday I did NOT remember this old thread ( 1 year ago when I setup the 12G tank) at BOSTON REEFERS. After the comments I reduced the LED power and the guy recovered the green color.

Now the coral has a yellowish color. What I will do now is a light reduction (T5) of 1 hour and see what happens. I will go slowly

The T5 are now ~6 months old and I will be changing them next month.

This was my thread at Boston Reefers: http://www.bostonreefers.org/forums/showthread.php?133960-Is-this-coral-bleaching&highlight=color

The coral pictured below and in the BR thread is the same one of my first posting of this thread. The mini-colony grew. The first picture below is from the day I glued to the rock and secreted all that mucus. The second was 1 month and a half later.





Daniel

 

[sirrealism]

Great info as i have the same coral with the same problem. Really I didnt see it as much of a problem as it was still growing but it has lose that deep green. Now that I think about it i have this going on with some other birdnests. Time to turn down the lights.

 

[Danreef]

I have reduced my total light time from 13 to 12 hours. The T5 will be ON for 8 Hours and the LEDs for the total of 12 hours. In this way the tank will have 2 hours of sunrise and 2 hours of sunset and 8 hours full lighting.

Let see what happens. The coral with this yellow color is very pretty, more than with the green color. Let see if it stay yellow or return to green. I do not want him go to white (bleaching).

Will update when I see a change or no change at all and stay yellow. I will give some weeks.

Daniel

 

[Oxylebius]

Based on these two articles from Coral Science, recovering from bleaching can occur over time if the coral is fed food.
http://www.coralscience.org/main/articles/climate-a-ecology-16/coral-bleaching
http://www.coralscience.org/main/articles/nutrition-6/how-corals-feed
Additional article:
http://www.advancedaquarist.com/blo...hing-is-highly-dependent-on-food-availability

Takeaway
Corals have developed several unique ways of feeding; they receive nutrients from symbiotic algae, capture particles such as plankton, and take up dissolved substances from the water.

During bleaching events, there are less numbers of symbiotic algae to capture food, if bleaching progresses coral can starve to death. Since coral can take in food such as plankton, feeding your coral during bleaching events keeps the coral alive for the length of time it takes the coral to rebuild the symbiotic algae in their polyps again.

The research results from the third article above indicated that corals that actively fed were significantly better at rebounding from the bleaching episode. Fed corals’ chlorophyll a levels completely recovered to pre-bleaching levels whereas unfed corals’ levels only rebounded to two-thirds this level. Protein levels as well rebounded completely in fed corals. Unfed corals had much lower protein levels throughout the study.

Article on feeding scleractinian corals (w/videos of sps feeding):
http://www.advancedaquarist.com/2013/12/aafeature

 

[Oxylebius]

I have reduced my total light time from 13 to 12 hours. The T5 will be ON for 8 Hours and the LEDs for the total of 12 hours. In this way the tank will have 2 hours of sunrise and 2 hours of sunset and 8 hours full lighting.

Let see what happens. The coral with this yellow color is very pretty, more than with the green color. Let see if it stay yellow or return to green. I do not want him go to white (bleaching).

Will update when I see a change or no change at all and stay yellow. I will give some weeks.

Daniel

Based on my reading of bleaching, it is like a domino affect. Once triggered all polyps in a coral tend to react and expel their symbiotic algae, what you want to do is to stop this reaction. If it were me, I think I would either move the coral to a lower location in the tank or minimize the light level even more then you have. At least for the next two weeks and then re-evaluate to see if the coral has gotten worse. Maybe back off the T5s to 6b hrs a day. Not sure what LED lighting you have, blues or mixed colors, but also maybe backing them down to 10 hrs from the 12 hrs. Just for the time being.

 

[Danreef]

Oxy.... there is no space where I can place that coral below. He is in the middle of the tank and below him is full of others corals.

I will reduce more the light at my return on Friday. But neither I am 100% convince of that because the other corals are doing OK. To benefit one I do not want to affect others. Do you agree ?

I need to find a baLance in the tank that fit most. If he is out of that balacne then I will need to replace the coral. But before that I will see if he stay yellow or go back to the green or........cross your fingers !!!