why no white corals?

[Randy Holmes-Farley]

There are actually some naturally pale/white corals that are zooxanthellate--Cycloseris, Pleuractis granulosa, and Sinuorota hexagonalis being a few of them.
Cycloseris sp.; Guam | Credit: Marisa Agarwal

Pleuractis granulosa; Egypt | Credit: Ingo Rogalla

cf Sinuorota hexagonalis; Kwajalein Atoll | Credit: Scott & Jeanette Johnson

Except for the brown parts, some of those corals do not look healthy to me, but perhaps they are just among those corals with low zoox levels.

 

[encrustingacro]

Except for the brown parts, some of those corals do not look healthy to me, but perhaps they are just among those corals with low zoox levels.

The corals are not bleached, as they aren't highlighter white. There are pigments which make corals pale, although they are unknown. P. granulosa is almost always pale/cream-colored, and Cycloseris has a white color morph. We just aren't used to pale/white corals, as they are not often imported in the hobby.

 

[Randy Holmes-Farley]

The corals are not bleached, as they aren't highlighter white. There are pigments which make corals pale, although they are unknown. P. granulosa is almost always pale/cream-colored, and Cycloseris has a white color morph. We just aren't used to pale/white corals, as they are not often imported in the hobby.

That may be true. Cream colored corals are often fine. My fox coral grew rapidly and was cream colored.

But I’m not convinced corals in those photos are in good shape.

 

[encrustingacro]

That may be true. Cream colored corals are often fine. My fox coral grew rapidly and was cream colored.

But I’m not convinced corals in those photos are in good shape.

I've seen enough photos of these species to know that they are fine. Generally, you would see skeleton or dying flesh if they weren't in good shape. It seems that pale corals are more common in inter-reef habitats with sandy bottoms and more sediment.

P. granulosa are virtually always pale, and the only Sinuorota specimens (not many; these are rare) I have seen are pale.
White is a pretty common color in Cycloseris:

Genus Cycloseris

Cycloseris from Kubu, Bali on November 29, 2023 at 01:31 PM by Wayne Leifert (scubawayne)

www.inaturalist.org

Genus Cycloseris

Cycloseris from Daanbantayan, Cebu, Philippines on February 20, 2024 at 11:41 AM by Ben Illis

www.inaturalist.org

Genus Cycloseris

Cycloseris from Napoleon Reef, Pemuteran, Bali, Indonesia on March 27, 2024 at 09:46 AM by portioid

www.inaturalist.org

Genus Cycloseris

Cycloseris from Sidem, Tulamben, Bali, Indonesia on January 21, 2024 at 10:45 AM by portioid

www.inaturalist.org

Genus Cycloseris

Cycloseris from Sidem, Tulamben, Bali, Indonesia on January 21, 2024 at 09:25 AM by portioid

www.inaturalist.org

Genus Cycloseris

Cycloseris from Basse Caledonienne on December 29, 2023 at 08:47 AM by Damien Brouste

www.inaturalist.org

Cycloseris cyclolites

Cycloseris cyclolites from South Province, New Caledonia on August 19, 2023 at 11:06 AM by Damien Brouste

www.inaturalist.org

Cycloseris cyclolites

Cycloseris cyclolites from South Province, New Caledonia on August 19, 2023 at 10:20 AM by Damien Brouste

www.inaturalist.org

Genus Cycloseris

Cycloseris from Dili Barat, TP-DL, TL on April 8, 2023 at 09:27 PM by ivansls. 14m

www.inaturalist.org

Cycloseris vaughani

Cycloseris vaughani from Kwajalein Atoll, RMI on April 27, 2014 by uwkwaj

www.inaturalist.org

Genus Cycloseris

Cycloseris from Kwajalein Atoll, RMI on July 14, 2014 by uwkwaj. ID tentative

www.inaturalist.org

Genus Cycloseris

Cycloseris from Kwajalein Atoll, RMI on July 18, 2016 by uwkwaj. ID tentative

www.inaturalist.org

Cycloseris cyclolites

Cycloseris cyclolites from Kwajalein Atoll, RMI on July 14, 2013 by uwkwaj

www.inaturalist.org

Genus Cycloseris

Cycloseris from Tulamben - Karangasem, Bali, Indonesië on March 14, 2023 at 11:15 AM by Glenn Biscop

www.inaturalist.org

Genus Cycloseris

Cycloseris from Jl. Raya Senggigi, Malaka, Kec. Pemenang, Kabupaten Lombok Utara, Nusa Tenggara Bar. 83352, Indonesia on January 14, 2023 at 11:57 AM by Alwan Syah

www.inaturalist.org

Genus Cycloseris

Cycloseris from Anse Vata, Nouméa 98800, Nouvelle-Calédonie on October 25, 2020 at 01:28 PM by Johan Bas

www.inaturalist.org

Genus Cycloseris

Cycloseris from Western Division, Fiji on February 6, 2023 at 02:59 PM by Debra Baker. Dive along our anchor chain. Murky, silty. Sand, small patches of coral, rubble. Guessing.

www.inaturalist.org

Genus Cycloseris

Cycloseris from Tepava on January 22, 2023 at 08:53 AM by Damien Brouste

www.inaturalist.org

 

[Randy Holmes-Farley]

I certainly accept cream colored corals as being healthy. I’ve had many myself. Bubble corals, for example. They just are not white. Maybe that is taking the original question too literally, but to me, this is a white coral:

Deep-Sea Corals: Biology - Coastal Conservation League

We’re continuing our journey to the depths of the Blake Plateau and its fascinating deep-sea coral ecosystem by diving into the biology that makes deep-sea corals so unique. No need to have a background in biological sciences, just your excitement for all things Under the Sea is required! The...

www.coastalconservationleague.org

Large reef building stony coral, known as Lophelia pertusa, are naturally white!

 

[Seansea]

Lazy daisy pipe organ coral. Straight up white polyps. Mine had some green in it. Died after a year mysteriously. Think I had it in too low a flow area and they like alot. Super cool looking tho in a tank of crazy colors stood out.

 

[i cant think]

with all the coral colors that are out there, and different types. why is there no white coral?
and when I say white, I'm talking healthy coral that is meant to be white.
you can find every color of the rainbow, but that one.

unless there is white coral out there, but I've never seen any

Ice-Fire Acropora echinata is somewhat white.

 

[Naekuh]

The Original PomPom Xenia is white, and its pretty as heck, and it pulses on top.

But it will probably drive you crazy on how fast they spread, and how difficult it is to get off.

 

[encrustingacro]

I certainly accept cream colored corals as being healthy. I’ve had many myself. Bubble corals, for example. They just are not white.

We are just not used to seeing pale but healthy corals, as we don't see them in the hobby. Sometimes, corals are pale or have brighter colors because they rely on feeding for a higher percentage of their energy needs, so they have less zooxanthellae in their flesh. I'll ask some coral biologists and get back to this.

 

[encrustingacro]

@Randy Holmes-Farley Okay, I asked Joe Rowlett about this. I was wrong about white in corals being caused by a pigment; apparently, it's more of "the absence of darker pigments and a reduced density of zooxanthellae." Joe mentioned that pale/white corals "tend to occur in silty habitats," likely because more suspended food means less zooxanthellae is needed for energy production.

 

[Formulator]

Just to address the obvious problem with white: to be photosynthetic one needs to absorb light.

To be pure white you cannot absorb light. Hence lack of white plants and other photosynthetic organisms.

Some may be quite pale and have a lot less ability to photosynthesize than others, but still need to be off white.

There certainly are colorless and white NPS (nonphotosynthetic) corals. I had some come in on my live rock.

Can’t believe it took so long to state the obvious… This is the answer.