SPS Spotlight: “Pearlberry” – Beautiful, Mysterious, And Finicky

by Mike Lauderdale

The Pearlberry is one of those corals that most people look at and think “It’s soooo beautiful – I’m going to try my hand at keeping SPS!” For sure, this is an inspiring coral – it is one of the most spectacular corals in our system, and we sure do love to stare at it. But as most SPS keepers know, the decision to move to the dark side and start keeping the “colored sticks” is not one to be taken lightly. SPS corals can be very demanding and frustrating; even with high-quality water parameters, great equipment, and obsessive system maintenance, finicky Acropora species can punish the hobbyist with slow growth, poor coloration, pest infestations, and scary afflictions like “rapid tissue necrosis”.

It isn’t a lost cause, though. By doing your homework, being willing to do the hard work and make the necessary investments, you can be rewarded with some of the most beautiful species in the animal kingdom. Despite being difficult to keep, Pearlberry can be one of those crown jewels in your SPS system – it has a gorgeous pearlescent skin with absolutely lovely lavender corallites and delightful contrasting-colored polyp tentacles. Couple this with the desirable bushy, tabling structure and this is one enviable specimen for any reef tank.

Figure 1 – ORA Pearlberry colony from the author’s 300g reef aquarium

Pearlberry Species – the mystery
ORA is accredited with being the wholesaler who brought Pearlberry to the hobby. The actual species of the Pearlberry Acropora has long been a subject of conversation. ORA claims1 that the coral “resembles Acropora desalwii” – true enough, but many feel this assertion to be questionable. Several colonies of Pearlberry I have seen (including the one in my system) resemble Acropora batunai2. Consider figure 2 – a wild colony of A. batunai. Visual inspection alone can be misleading and inconclusive when it comes to making a positive identification of SPS corals, but this certainly looks like the Pearlberry in Figure 1.

Figure 2 – A. batunai from AIMS Coral Fact Sheet, picture © Charlie Veron

Now take a look at figure 3. This is a colony of Acropora desalwii from our system. Do you notice any differences in growth form from the Pearlberry in figure 1? Both are certainly beautiful specimens, with the light-colored skin on the base, bushy plating growth form, and lovely pale bluish corallites. But when you really look closely, there are some differences. Environmental conditions can drastically affect growth forms and other visual characteristics of corals, both in the wild and in captivity. This really makes it challenging to compare and contrast species. Part of what makes SPS-keeping fun and rewarding is the knowledge and skills that are developed by observing corals and their behavior closely.

Figure 3 – Acropora desalwii

Scientific references rely upon several data sources to differentiate between species, but most are visual. Behavioral data are difficult to observe and capture in the wild, and undoubtedly this has limited our documented knowledge of many corals. This fact, coupled with the recent availability of genetic testing is helping to shape our understanding of the evolution and differences of these animals across the earth. AIMS usually includes skeletal pictures of corals in their fact sheets, and this certainly helps aid in the differentiation and identification of coral species. Even with that “naked” level of detail, we can still have trouble drawing positive conclusions. Take a look at Figures 4 and 5, the skeletal pictures from AIMS for A. desalwii and A. batunai.

     Fig. 4 – Skeletal view of A. batunai © AIMS                 Fig. 5 – Skeletal view of A. desalwii © AIMS 

Both corals grow in corymbose or tabling colonies. Likewise, both corals show similar branching patterns and corallite structures. The light-skinned base, and pale coloration patterns are also similar. The reader is left to do your own research and draw your own conclusions. I am sure the debate will continue on until confirmed with genetic testing. Regardless of which Acropora species is truly attributed to the beautiful Pearlberry, hobbyists report similar experiences in keeping them. These reports align with a coral that comes from shallow, protected environments; they tend to grow with fairly delicate structure for a top-water coral. They also tend to appreciate higher light and higher flow, and of course very stable and high-quality water parameters. Pearlberry can be quite difficult for many aquarists to keep successfully in the captive environment as it can be easily upset by changes in water quality or lighting conditions.

        Quick Stats:
Care level:         difficult
Lighting:           med/high
Placement:       med/top
Flow:                 high
Temperature:    72-76
Alkalinity:          7-9 dKH
pH:                   7.8 – 8.3
Salinity:            1.023 – 1.026

Summary
ORA’s Pearlberry is a delicate SPS species that is a real attention-grabber. Regardless of its true nature, most everyone can agree it is one of the most beautiful corals that have yet to be domesticated. The difficulty in growing it contributes to the prices it commands in the market and its relative scarcity. If you are a seasoned SPS keeper, the Pearlberry can be a prized addition to your system that can challenge your skills.

References:
1 Oceans Reefs & Aquariums
2 Australian Institute of Marine Science
3 Wiki Marino

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