what is bleaching?

[BradsOcean]

title

[buck50bmg]

Its when a SPS coral expels all of its zooanthele(sp) algae. Basically it goes completely white, the algae is what gives the coral its color....so no algae....no color.

[Aquarist007]

<a href=showthread.php?s=&postid=12592991#post12592991 target=_blank>Originally posted</a> by buck50bmg
Its when a SPS coral expels all of its zooanthele(sp) algae. Basically it goes completely white, the algae is what gives the coral its color....so no algae....no color.

agreed

here is a little more reading if you wish to:

http://en.wikipedia.org/wiki/Coral_bleaching

[BradsOcean]

so the corals not dead or unhealthy? just discolored? also, can't it happen to other corals, not just sps? I thought i saw an anemone that someone said was bleached..

[buck50bmg]

No bleaching is dead. There are 2 kinds of white.......a beautiful white (dead) and a offwhite (close to dead unless you can fix why it went white)

When we say bleach we mean dead or partially (like from the bottom up) Sometimes they can be saved.......

As for softies...not bleaching so much as poor health, as for the anemone.....dont think so....

[BradsOcean]

so what causes bleaching? ive heard it you increase the light too much? does that sound right?

[buck50bmg]

Stress....could be Temp, PO4 shift, Light....anything, just go slow.

[greenbean36191]

Bleaching is when the symbiotic algae in corals, anemones, or clams is expelled. The animal is still very much alive and still has its own pigments which are what gives it color. The colors are washed out and translucent though. It's not a healthy situation though because the algae provide a significant portion of the carbs for the host and without them the host is essentially starving. If the initial stressor is corrected though, the zooxanthellae can repopulate the host through division or by being taken up from the water. If the stressor continues or bleaching happens too frequently, the animal will die.

Bleaching is a general stress response and can be caused by numerous things- high light, low light, high temp, low temp, low flow, chemicals, diseases, etc.

[seapug]

Just to add to greenbean-- Bleaching is a loss of pigmentation, not tissue. It is reversible. RTN/STN is the complete peeling of the tissue that leaves a white skeleton. Not reversible.

[sk8boarder]

well anemones can get bleached. caused by poor water conditions or other things. since nem has no algae to feed on u have to feed it constantly so it survives. but sooner or later it will get new zooxanthellae

[Kyattsuai]

Interesting there should be a post on this today. I went to the LFS today cause they get new stuff in on Wednesday.s ;-)

Anyway there sat a beautiful toadstool. But it was stark white, not a hint of color on it. It came in that way yesterday. Maybe i should offer to take it of their hands and see if I can bring it back. The Polyps were out searching for food.... :-)

[seapug]

There are some toadstools that look white normally. I have a huge long polyped one in my 90 gallon that's been snow white for the past 1.5 years. It's about 5 times the size of when I bought it so I know it's perfectly healthy. One of those anomalies, I guess.