Red Acros are one of the rarest color forms you can find in captively grown Acropora species, which is why species such as the ORA Red Planet, the Red Dragon acro, and the raspberry red Millepora acros are so popular in a field of otherwise blue and green SPS corals. With red color being such a rarity among Acropora, you can imagine our surprise when we came across a handful of different red strains of Acropora at Kwajalein Atoll which represented at least five different species.
We’ve already told you about the Red Devil Acropora tenella, the red forms of Acropora rongelapensis and the Ebeye Special Acropora microclados, but there were a few more. The video above shows a colony of Red Devil Acro which has an ‘unnatural’ red glow at the 50 foot depth where the red acropora are mostly often sighted.
The two other Red Acros sighted at Kwajalein included an unidentified colony which had the same red color scheme as many of the Red Devil Tenella and Red Ronggies; red branches with blue tips or growth margins and bright green polyps. This particular coral, being unidentified but otherwise not standing out as a unique species could very well be the result of hybridization, or some other poorly known phenomenon such as the coral chimera we also documented.
The fifth strain of Kwajalein red acros is a beautiful red Acropora speciosa which is very rare, but really hard to miss when it is found. With total of 24 hours spent underwater, diving and looking for cool corals, we only came across two colonies of the red Acropora speciosa and these had a beautiful, rich red body and branches and elegant little yellow tips to the corallites.
Genetics is a complicated field of science and it is even more complicated when coral genetics are considered, but we do know that corals are capable of doing a lot of ‘gene mixing’ and reticulate evolution is a theory that applies particularly to corals. That said, we hazard to guess that perhaps in the central pacific ocean, including the Marshall Islands, there could be a lot of gene mixing going on to help propagate the ‘red color gene’ among a wide group of stony corals in a way which is not present in other coral regions of the world, at least not as far as red color is concerned.