This coral is still with me, which is over 11 years since I rescued it. During that time, it has had quite the identity crisis. When I first rescued it, I wrote on an old blog, “Many large polyp stony corals are difficult, if not impossible, to identify without examination of a coral’s skeleton. Thankfully, the genus Trachyphyllia is not, as it only has one species: geoffroyi.” HAHAHA, oh how much we have learned since then! So, not only did this dying Acanthastrea coral go through an amazing rehabilitation, but it also fell into a few different genera along the way.
Assessing Dying Coral Health:
When I found this coral at a Local Fish Store (LFS) in November, 2010, I believed it was a Trachyphyllia geoffroyi, mostly due to its hourglass shape (and lack of good reference material on coral septa patterns at the time).
Although it is pure speculation, I believed the coral’s condition was due to rapidly deteriorating water conditions. The freshly exposed skeleton showing bright in white suggested something drastic changed, and the fairly uniform amount of exposed skeleton suggested the source of the problem surrounded the coral. The good coloration (albeit slightly bleached) indicated that lighting and some infections were not likely. But, the tight skin against the skeleton along with the gaping mouths suggested the coral was probably not eating and possibly acting defensively to reduce its exposure to poor water quality. (For more information, see Assessing Coral Health: An Introduction.)
Quarantined Acanthastrea Coral:
Poor water conditions could have meant allelopathy (chemical warfare between corals), high nitrates/ phosphates, unbalanced alkalinity/ calcium/ magnesium, et cetera. To treat this coral I purchased for $10, I decided the best course of action was just a good aquarium. After completing my coral examination and dip, I cut the coral’s septa (the teethy-ridges). I have found that if a large polyp coral was to suddenly inflate in excessive flow, the flesh will easily rip on the septa. With a sick coral, one small tissue tear can continue to rip or become infected and quickly lead to the demise of the coral. To prevent this, I carefully trimmed back the septa and removed all sharp points. The coral could then expand with little difficulty. Additionally, corals seem to have more ease in growing back over the existing skeleton this way.
Acanthastrea Coral in Grow-out:
Only a few weeks later (21 November 2011), the coral was inflating and starting to grow over the exposed skeleton.
I regularly fed it pellet food, as highly processed food seems to be easier to digest for injured corals. Notice the orange ring developing! (30 January 2011)
The progression in only a couple weeks was rapid. The coral nearly covered all previously exposed skeleton, by only 24 February 2011 (about four months after I purchased it). However, by this point, I was starting to question my initial assessment of Trachyphyllia geoffroyi. It was starting to look more like a Lobophyllia, but it was still more hourglass-shaped.
Previously Dying Acanthastrea Coral, Fully Rehabilitated:
By October 2011, I realized I was probably wrong about the genus. It was splitting more like a Lobophyllia. But at that point, I really didn’t care, as the coral was fully healed (less than a year later!)
Not just Surviving, but Thriving!
Although this coral’s recovery was impressive under daylight conditions, under actinics it became a showstopper!
Around 2016, several studies and articles starting making me rethink the classification on this coral. Rather than Lobophyllia pachysepta, it seemed to fit more within Acanthastrea (Huang, et al., 2016).
Here’s the previously dying Acanthastrea colony in 2021, which was still large despite a few fraggings over the years!
Conclusion:
From nearly dead to thriving in less than a year… to over 11 years later… this coral continues to awe and confuse me! This dying Acanthastrea coral’s rehabilitation also went from Trachyphyllia geoffroyi to Lobophyllia pachysepta to Acanthastrea pachysepta, or at least so I think!
References
- Huang, Danwei, Roberto Arrigoni, Francesca Benzoni, et al., “Taxonomic Classification of the Reef Coral Family Lobophylliidae (Cnidaria: Anthozoa: Scleractinia), Zoological Journal of the Linnean Society, 2016, 178, 436-481.
- Arrigoni, Roberto, Francesca Benzoni, Danwei Huang, et al., “When Forms Meet Genes: Revision of the Scleractinian Genera Micromussa and Homophyllia (Lobophylliidae) with a Description of Two New Species and One New Genus”. Contributions to Zoology 85.4 (2016): 387-422.
