Starry Cup Coral, Echinata Coral, Rainbow AcanthastreaFamily: Mussidae Acanthastrea echinataPhoto © Animal-World: Courtesy Greg Rothschild
The Acan Echinata is a very attractive LPS coral that comes in all the colors of the rainbow!
The Acan Echinata Acanthastrea echinata is a colorful large polyp stony (LPS) coral in the Mussidae family. They are found in some intense oranges to intense green and red combinations.The Echinata Coral is the second most popular and sought after of the Acanthastrea species, following the Acan Lord A. lordhowensis. Some descriptive names the A. echinata are known by include Echinata Coral, Starry Cup Coral, Artichoke Coral, Pineapple coral, Rainbow Acanthastrea, Rainbow Acan, and Acan Brain Coral.
A. echinata has been propagated in captivity with great success, leading to a variety of colors. Captive bred specimens can have lavenders (gray), oranges (rust), and bright green combinations and different colored specimens have even been fused or grafted. Propagated specimens are called such things as Orange Crush Acan Echinata, Rainbow Acan Echinata, Lavender Green Acan Echinata, and so forth.
The Acan Echinata is one of the easiest of the LPS (large polyp stony) corals to care for. They are not at all demanding and will readily grow new polyps. They do not need to be fed since they use the dissolved organics in the tank for nourishment. Try to avoid housing with soft corals as they do not do as well in their presence, and some will die if the softy population is too high. Provide a low water movement and moderate lighting. Do not use metal halides since the Acan Echinata will not fully open under lighting that is too strong.
The Acanthastrea species are fairly common in nature and have been regularly available in the aquarium trade for many years. They are collected in similar numbers as other Mussidae corals including the well known Lobophyllia and Blastomussa species. However, Acanthastrea corals have often been misidentified. They are easily confused with some of these other members of the Mussidae family as well as species from the Faviidae family, Consequently Importers, retailers, and ultimately reef keepers will often simply trade them as 'brain corals'. Those that are advertised as Acanthastrea are generally quite pricey.
Species: Acanthastrea echinata
Acanthastrea Coral Information: The Acanthastrea genus was described by Edwards and Haime in 1848. There are about 16 species, approximately 13 of which are true species with 4 being found around Australia. Species include: A. amakusensis, A. bowerbanki, A. echinata, A. faviaformis, A. hemprichi, A. hemprichii, A. hillae, A. horrida, A. ishigakiensis, A. lordhowensis, A. maxima, A. minuta, A. regularis, A. rotundaflora, A. simplex, and A. subechinata. A. micromusa it is not actually in the Acanthastrea genus due to its skeletal structure and as of yet has not been added to the list.
Some common names the Acanthastrea corals are know for are Brain Coral, Bullseye Coral, Moon coral, Pineapple Coral, Starry Cup Coral, Pineapple Starry Cup Coral, and Pineapple Brain Coral. The Acanthastrea genus has been propagated in captivity.
The A. echinata was described by Dana in 1846. Some common names these corals are know for are Echinata Coral, Pineapple Coral, Artichoke Coral, Starry Cup Coral, Acan Brain Coral, Rainbow Acanthastrea, Rainbow Acan, and Favia. The A. echinata has been propagated in captivity with great success, leading to a variety of colors. Some reef farmers have named theirs Orange Crush Acan Echinata, Rainbow Acan Echinata, Lavender Green Acan Echinata, etc.
Where Acanthastrea Corals Are Found: The Acanthastrea echinata are found from the Red Sea to the Marshall Islands and the Tuamotu Archiplego; also around Australia in the Great Barrier Reef, the Coral Sea, the Elizabeth Reef in the east, and the Houtman Abrolhos Islands.
Acanthastrea Coral Habitat: The Acanthastrea echinata live in a wide range of habitats on the reef, and are found at depths of 0-98 feet (0 - 30 m). They rarely occur over 3 feet (1 m) in diameter. They feed at night, extending thick tangled tentacles.
The A. echinata is not on the IUCN Red List of Endangered Species.
What do Acanthastrea Corals look like: The A. echinata has corallites (skeleton formation under each polyp) that have even walls, height wise, so there is a more uniform appearance to the coral. Inspecting the polyps of the A. echinata when not fully expanded reveals that these walls are being shared, thus contributing to the identification. When the polyps retract, due to their fleshy polyps, little folds appear almost like an accordion. They come in rust, brown and green, but captive frags can have lavenders (gray), orange (rust), and bright green combinations.
Be careful when selecting your specimen of A. echinata, as It can easily be confused with Favites, Favia, and Moseleya corals unless the the fleshy polyps are expanded. On the other hand, it can also be easily confused with Blastomussa and Lobophyllia species if the polyps are expanded. Unlike these last two coral types, the walls of the Acan Enchinata are not "separate" on its skeletal structure, rather all its corallite walls are shared between the individual polyps. This can make Identifying them a little tricky, because when their polyps are fully expanded it gives the illusion of having separate corallite "walls". In this instance, being able to see the skeletal structure showing shared walls would be helpful.
Some colonies of A. echinata can reach 3 feet (1 m). Life span is unknown.
Acanthastrea Coral Care: Like other Mussids, the A. echinata is easy to care for, making them an excellent choice for the beginner. Provide moderate lighting, as strong light will prevent the polyps from opening fully. Water flow should be low as well. Like other members of the Mussidae family, the polyps tentacles come out at night to feed.
Acanthastrea Coral Feeding: The Acanthastrea genus, like other large polyp stony (LPS) corals, have developed several feeding strategies. Through a symbiotic relationship with a marine algae, known as zooxanthellae, they receive some of their nutrients. They also capture planktonic organisms, food particles from the water column, and can absorb dissolved organic matter.
In captivity, A. echinata feed mostly on nanoplankton and dissolved organics in the water, though like Ricordea (a type of Mushroom Coral), they can be fed zooplankton and very small prey.
Typical water changes of 20% a month, 10% biweekly, or 5% weekly are needed. It has been noted that 5% weekly water changes replenish many of the needed additives and it is ultimately cheaper than purchasing additives for the water. With higher concentrations of coral with calcareous skeletons though, there may be a need put in additional additives to maintain proper levels for good growth.
The Acan Enchinata will not do as well in a "pristine" water environment with no fish, as fish provide an source of nitrogen that they need to thrive. Calcium nitrate is also appreciated. Note that this is different from just plain calcium that we all add to our tanks for our corals.
The following water supplements are suggested for Acanthastrea species:
- Calcium: 400 to 450 ppm. If a large poly stony (LPS) coral does not have enough calcium, it will not grow. (Seachem makes a calcium additive that states 385 as sufficient)
- Alkalinity: 3.2 - 4.8 MEQ/L (8 to 11 dKh, 10 is recommended)
- Phosphates: 0, zero.
- Magnesium: 1200 - 1350. Magnesium makes calcium available, so if your calcium is low, check your magnesium levels before adding any more calcium.
- Strontium: 8 - 10
A well-feed live rock/reef environment is what is needed for your Acanthastrea Coral, along with some fish for organic matter production, and dissolved organics. A mature tank is recommended.
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Be sure to have proper water movement and lighting. Provide a low water flow and moderate lighting for the best health. Do not use metal halides since the Acan Echinata will not fully open under lighting that is too strong. This is an aggressive species, extending their sweeper tentacles at night. There needs to be plenty of space between it and other corals.
- Minimum Tank Size / Length: 29 gallon (106 L) nano reef or larger
- Marine Lighting: Medium, do not use metal halide
- Temperature: 76° - 83° F (24° - 28° C)
- Salinity / Specific Gravity: 1.023 - 1.025
- Water Movement: Low
- Water Region: Bottom of the aquarium
The Acanthastrea genus is aggressive towards other corals. The A. echinata will get along with their same species, but typically different colors of different species tend to be more aggressive. They do need to be kept well away from other corals. They have tentacles that come out at night and sting nearby corals. Also, if close enough they will invert their stomach onto a nearby coral and digest the tissue right out of the skeleton. Once their "enemy" has been digested, they retract their stomach back inside.
The Acanthastrea genus does not do as well in the presence of soft corals. Some Acan species will die if the population of softies is too high.
The large polyp stony (LPS) corals are hermaphrodites, male and female within the same organism, and can reproduce both sexually and asexually. In the wild they reproduce sexually by releasing eggs and sperm at the same time, resulting in a fertilized egg which then forms into a free-swimming planula larva. Eventually the planula larvae settles onto the substrate, becoming plankters. This then forms a tiny polyp which begins to excrete calcium carbonate and develops into a coral. Planula larvae are extremely vulnerable to predation, and very few survive.
The Acanthastrea genus are hermaphrodites that use external fertilization in the wild, but this has so far not been duplicated in man made systems. This genus reproduce asexually as well. In captivity, the A. echinata will drop tissue when stressed, in an attempt to propogate.They can also be propagated by fragmenting.
Propagation is very easy. Taking care to have clean or gloved hands, each polyp can be cut down the center of the polyp, through the mouth and can be cut in to halves or quarters. You can use a sharp scalpel, razor blade or dremel. Place the newly fragged polyp on the sand back in the main display. Putting them in a separate, "sterile" tank is not a good idea, since they need dissolved organics to survive. Make sure they have low water flow to help them heal.
The A. echinata are attractive and durable when their needs are provided for. They are pretty hardy, but can starve to death in a nitrate free tank.
Acanthastrea Corals for Sale: The A. echinata is very easy to find at pet shops and on line. The cost online varies, depending on retailer, size, and/or color. One example would be $99.99 USD for a 6.5" (16.5 cm) piece.
- Animal-World References: Marine and Reef
- Anthony Calfo, Book of Coral Propagation, Volume 1 Edition 2: Reef Gardening for Aquarists, Reading Trees; 2nd edition, 2007
- J.E.N. Veron, Corals of Australia and the Indo-Pacific, University of Hawaii Press; 2 Rev Ed edition, 1993
- Eric Borneman and Anthony Calfo, Good Lordhowensis!!, Reefkeeping, an online magazine for the marine aquarist, reefkeeping.com, copyright 2008
- Justin Credabel, Coral Fusion and Grafting, Reefkeeping, an online magazine for the marine aquarist, reefkeeping.com, copyright 2006