Acanthastrea are some of the most mis-identified corals in the reef. These corals have been misidentified by hobbyists and merchants alike for many years. Acanthastrea is a relatively large genus in the family Mussidae, and contains roughly 12-15 species. Acanthastrea are not easy to distinguish from species in several other genera, and even families, of corals.
Acanthastrea generally has corallites between 8-15 cm in diameter. Because these corals have very fleshy polyps, identification to genus is difficult to impossible, as the characteristics that would confirm a positive identification are hidden. Although there are some exceptions, Acanthastrea are found in many locations on the reef, and although some species can be found deeper, most are collected from shallow water to about 20 m in depth.
In marine saltwater aquariums, Acanthastrea are tolerant of diverse conditions and can thrive in strong or subdued lighting and water flow situations. Acanthastrea are voracious predators with strong nocturnal feeding responses. They are very competitive in their ability to extrude mesenterial filaments. Great care should be taken when placing the Acanthastrea near other sessile organisms.
Because of the often misinterpretation of the Acanthastrea, the values of this type of coral have been extremely hyper-inflated throughout aquarium enthusiasts. One expert has been quoted as saying that for the price of what a few colonies of Acanthastrea are being sold for today, he could “fly across the world on a long vacation to Sulawesi” and “with a little effort bring back Acanthastrea I collected using existing exporters.”
Acanthastrea will readily accept feedings of minced meaty foods such as shrimp, mysis and squid. Though regular feeding of Acanthastrea is not required, it will help its growth. Acanthastrea also seem to react better to higher levels of magnesium (1250-1350 ppm).
The propagation of Acanthastrea is very easy. Wet tile saws, band saws and dremel tools may be used to make the appropriate cuts. Simple agitation of the coral will cause the polyps to retract, at which time it is safe to cut out the desired number of polyps. Once the Acanthastrea frag is made, it can be left as is in the sand bed where it will grow its own calcium skeleton or affixed to a piece of live rock where it will encrust over the rock, which is generally the preferred method.