Jim Greenfield, Großbritannien
Info
Anthogorgia caerulea is characterized by an exceptionally bright blue coloration; it is an azooxanthellate gorgonian that has not entered into symbiosis with zooxanthellae (Symbiodinium).
In zooxanthellate stony corals, the symbiotic, microscopic, single-celled algae belonging to the class of dinoflagellates are responsible not only for supplying the coral with energy but also for producing proteins.
GFP-like proteins in corals from low-light habitats as well as in azooxanthellate and deep-sea anthozoans suggest that these proteins fulfill a number of other functions in addition to UV light protection. Responsible for color
The blue color of $ at is caused by so-called chromoproteins (chromo comes from the Greek and means “color”; proteins are proteins.
See: https://pmc.ncbi.nlm.nih.gov/articles/PMC4949654/
Unfortunately, the first description of this coral beauty, “The gorgonians of the Sinai coast and the Strait of Gubal, Red Sea (Coelenterata, Octocorallia),” is not freely accessible, so it is not possible to obtain detailed data on the horn coral.
We therefore wrote to the photographers of the first two photos, Bernhard Dupont and Jim Greenfield, and asked for further information:
Bernhard Dupont on October 12, 2025:
Hello Andreas,
Since I was still a PADI Open Water diver at the time, I did not dive deeper than 18 meters. The diameter was between 50 cm and 1 meter.
Unfortunately, I can't tell you any more about this sighting...
Best regards
Bernard
Jim Greenfield:
Hi Andreas,
Although it was thirteen years ago, I can still remember this dive well and have refreshed my memory by looking at all the photos I kept from this particular dive in Adobe Lightroom.
However, I'm not sure if this will help you.
It was an area with a dramatic underwater landscape, with many steep walls washed by currents that reached deeper than I dared to go. The water was calm when we were there, and it was a relaxed dive with lots of gorgonians that I could point my camera at.
I can't remember this particular coral, but I can say that my dive buddy and I have an unwritten agreement that we don't dive deeper than 25 meters and preferably stay at a maximum of 20 meters (mainly to save nitrox and extend the dive, but we also don't want to make decompression stops).
All of this is a long-winded way of saying that it was highly unlikely that the coral was below 20 meters—I took a series of photos and I don't like to stay below that depth.
The size is a little hard to remember, but I set my camera and wide-angle lens to the same focal length and looked at various things around the house and compared them to the photo.
The best estimate is 60/70 cm high.
Basic information about the genus Anthogorgia:
Colonies are usually flat and net-like and up to about two-thirds of a meter high.
Others form dense, bushy tangles or loose, laterally branched fans. Colonies are generally delicate with thin branches.
The coenenchyme layer between the polyps is usually so thin that the black axis is visible through it.
Polyps:
Monomorphic, non-retractable, often very tall when contracted, and sometimes trumpet-shaped. Such contracted structures look like calyxes, but are actually the non-retractable polyps.
The polyps are covered with wart-like spindles, which are mostly boomerang-shaped and usually arranged in two rows along the body wall. When the tip of a spindle protrudes, it is smooth. In many species, the spindles at the tip of the polyp, just below the tentacle base, are very long and protrude, forming a conspicuous spiny “crown.” The back of the tentacles is densely covered with small, flat, boomerang-shaped sclerites.
The thin surface tissue (coenenchyme) contains small, wart-like spindles that can occur in sea urchins or capstan derivatives.
The sclerites are always colorless.
Color:
Bright colors such as yellow, orange, pink, red, or dark purple. Colonies are often multicolored, and the color of the polyps may contrast with the color of the coenenchyme. Azooxanthellate.
Habitat and distribution:
Rare. Found on deeper slopes, steep walls, and flanks and ridges washed by currents.
Source: OFT CORALS AND SEA FANS A comprehensive guide to the tropical shallow-water genera of the Central-West Pacific, the Indian Ocean, and the Red Sea Katharina Fabricius & Philip Alderslad
In zooxanthellate stony corals, the symbiotic, microscopic, single-celled algae belonging to the class of dinoflagellates are responsible not only for supplying the coral with energy but also for producing proteins.
GFP-like proteins in corals from low-light habitats as well as in azooxanthellate and deep-sea anthozoans suggest that these proteins fulfill a number of other functions in addition to UV light protection. Responsible for color
The blue color of $ at is caused by so-called chromoproteins (chromo comes from the Greek and means “color”; proteins are proteins.
See: https://pmc.ncbi.nlm.nih.gov/articles/PMC4949654/
Unfortunately, the first description of this coral beauty, “The gorgonians of the Sinai coast and the Strait of Gubal, Red Sea (Coelenterata, Octocorallia),” is not freely accessible, so it is not possible to obtain detailed data on the horn coral.
We therefore wrote to the photographers of the first two photos, Bernhard Dupont and Jim Greenfield, and asked for further information:
Bernhard Dupont on October 12, 2025:
Hello Andreas,
Since I was still a PADI Open Water diver at the time, I did not dive deeper than 18 meters. The diameter was between 50 cm and 1 meter.
Unfortunately, I can't tell you any more about this sighting...
Best regards
Bernard
Jim Greenfield:
Hi Andreas,
Although it was thirteen years ago, I can still remember this dive well and have refreshed my memory by looking at all the photos I kept from this particular dive in Adobe Lightroom.
However, I'm not sure if this will help you.
It was an area with a dramatic underwater landscape, with many steep walls washed by currents that reached deeper than I dared to go. The water was calm when we were there, and it was a relaxed dive with lots of gorgonians that I could point my camera at.
I can't remember this particular coral, but I can say that my dive buddy and I have an unwritten agreement that we don't dive deeper than 25 meters and preferably stay at a maximum of 20 meters (mainly to save nitrox and extend the dive, but we also don't want to make decompression stops).
All of this is a long-winded way of saying that it was highly unlikely that the coral was below 20 meters—I took a series of photos and I don't like to stay below that depth.
The size is a little hard to remember, but I set my camera and wide-angle lens to the same focal length and looked at various things around the house and compared them to the photo.
The best estimate is 60/70 cm high.
Basic information about the genus Anthogorgia:
Colonies are usually flat and net-like and up to about two-thirds of a meter high.
Others form dense, bushy tangles or loose, laterally branched fans. Colonies are generally delicate with thin branches.
The coenenchyme layer between the polyps is usually so thin that the black axis is visible through it.
Polyps:
Monomorphic, non-retractable, often very tall when contracted, and sometimes trumpet-shaped. Such contracted structures look like calyxes, but are actually the non-retractable polyps.
The polyps are covered with wart-like spindles, which are mostly boomerang-shaped and usually arranged in two rows along the body wall. When the tip of a spindle protrudes, it is smooth. In many species, the spindles at the tip of the polyp, just below the tentacle base, are very long and protrude, forming a conspicuous spiny “crown.” The back of the tentacles is densely covered with small, flat, boomerang-shaped sclerites.
The thin surface tissue (coenenchyme) contains small, wart-like spindles that can occur in sea urchins or capstan derivatives.
The sclerites are always colorless.
Color:
Bright colors such as yellow, orange, pink, red, or dark purple. Colonies are often multicolored, and the color of the polyps may contrast with the color of the coenenchyme. Azooxanthellate.
Habitat and distribution:
Rare. Found on deeper slopes, steep walls, and flanks and ridges washed by currents.
Source: OFT CORALS AND SEA FANS A comprehensive guide to the tropical shallow-water genera of the Central-West Pacific, the Indian Ocean, and the Red Sea Katharina Fabricius & Philip Alderslad
