Bleached Corals

[am00re34]

What would cause corals to bleach? I have a green bird’s nest that seems to be getting less green and more white every day. What causes this? The only thing I can think of that I changed recently was my bulbs.
And what can I do to fix this?

 

[florida joe]

Under stressful conditions, coral can expel is algal symbionts and this process is known as bleaching bleached corals often appear white simply because their tissue becomes more transparent and shows the white aragonite skeleton underneath the tissue itself is not white The loss of zooxanthellae involves significant intercellular changes that may disrupt many of the corals pigment components prolonged exposure to stressful conditions may be more then the coral can tolerate often bleaching is a last ditch attempt by the coral to survive

 

[am00re34]

i understand your point, but the coral was growing like crazy! so i would think if it was under stress it would stop growing, or is that not the case?

 

[jonthefishguy]

The stress was probably brought on by the intense light fluctuation from old to new spectrum. When changing bulbs, you should change them out one at a time over a period of several weeks (1 to 2 weeks in between for halides and HQI's or 1 week in between each for VHO's and PC's.) so that the corals and inverts become used to the brighter bulbs. Another suggestion is to reduce the amount of hours you have them on and raise them back to normal hours over a period of several weeks to a month. This again gives the inverts and corals a chance to not be shocked with intensity and cause it to bleach due to stress.

 

[bkvreef]

I recently purchased some live rock at a good deal. It turns out that there was a large colony of mushrooms on several pieces of the l.r. However, they were white! I have watched them and they open and close fine and the seller assured me that once they get accustomed to my lights (p.c. and t-5) then they will color up.

 

[florida joe]

Originally Posted by jonthefishguy
The stress was probably brought on by the intense light fluctuation from old to new spectrum. When changing bulbs, you should change them out one at a time over a period of several weeks (1 to 2 weeks in between for halides and HQI's or 1 week in between each for VHO's and PC's.) so that the corals and inverts become used to the brighter bulbs. Another suggestion is to reduce the amount of hours you have them on and raise them back to normal hours over a period of several weeks to a month. This again gives the inverts and corals a chance to not be shocked with intensity and cause it to bleach due to stress.
Excellent point

 

[am00re34]

is it to late now to back off on the lighting? maybe put in one of my old bulbs? (i kept them cause they still work). Or reduce the hours?

 

[peef]

Reduce the hours a bit it will help a bit.