The Merulina is a gorgeous Ruffled Coral with bright contrasting colors and a peaceful demeanor.
The Merulina amphiata is commonly called the Ruffled Coral, as well as names derived from its scientific name, starting with ‘amp’, ‘amplicata’, ‘ampliata’, and ‘amphiata’. Most of the Merulina corals are “frilly” and their common names are often descriptive of that. Some of the common names that the Merulina genus is known for are Ruffled Coral, Lettuce Coral, Ridge Coral, Merulina Coral, and Cabbage Coral.
The Merulina genus has a variety of growth forms. Most form colonies that have a ruffled plate or fanlike growth formation. But Merulina’s can also develop tall columns looking like a forest from the top, or short less developed columns that create a ruffled plate formation. The Ruffled Coral in the picture above has the ‘frills’, but is a bit knobbier than other varieties.
The colors of the Ruffled Coral M. amphiata are commonly green, pink, brown, and cream. Some colonies can possess several of these colors. These corals also have sweeper tentacles which come out at night. They are located on the coral’s edges or margins and can reach 3″ (8 cm).
Only an expert aquarist should attempt to keep this coral, it is not recommended for beginners. Although difficult to care for the Merulina species are some of the most beautiful corals, coming in blue, red, purple, green and pink. The Merulina genus comes from lagoon type environments, thus indicating that this should be an easy SPS to care for. On the contrary, it is very difficult to keep and doesn’t adjust well to changing conditions.
Propagation of M. amphiata has not been successful in captivity, due to this coral’s low survival rate. To compound the problem, they grow slowly. Typically wild caught specimens are available, although great care and research should be done before attempting this coral. Eventually propagators will be able to figure out their specific needs for long term care and this coral may become easier to keep.
Distribution / Background
Merulina Coral Information: The Ruffled Coral Merulina amphiata was described by Ellis & Solander in 1786. The Merulina genus was described by Ehrenberg in 1834. Some of the common names this genus are known for are Ruffle Coral, Lettuce Coral, Ridge Coral, Merulina Coral, and Cabbage Coral. They have not been successfully propagated in captivity.
Where Merulina Corals Are Found: The Merulina amphiata are found around Australia on the Great Barrier Reef, Coral Sea, Lord Howe Island, and to the Houtman Abrolhos Island. Merulina, as a species, are found in the Red Sea, Indian Ocean, and the west Pacific Ocean from the East China Sea all the way to the west, north, and east coasts of Australia, then east toward the Line Islands.
Merulina Coral Habitat: M. amphiata are found at depths down to 131 feet (40 m). They are found mostly in lagoons, but can also be found in most habitats around the reef.
What do Merulina Corals look like: The Merulina genus will form colonies that have a ruffled plate or fanlike growth formation. They also can develop columns that looks like a forest when viewed from the top. Some species have columns that are less developed and short, and grow with a ruffled plate formation. Thus both the column and plate-like formations can be found in the same colony of the same species. The grooves or valleys that are within the plated growth formation radiate from the center of the colony and form circular or arced growth lines. Their valleys are short and straight, yet can vary in length with different species. These corals also have sweeper tentacles which come out at night. They are located on the coral’s edges or margins and can reach 3″ (8 cm). At night the polyps are extended while feeding.
The M. ampliata has similar growth patterns. Although their valleys are straight and short, they spread like a fan and then separate. Their columns are much more defined and closer together, reaching up to 4″ (10 cm). The Ruffled Coral can form flat, plate-like formations as well.
The Ruffled Coral can be purple, pink, pale green, or brown with pale margins and contrasting polyps that are white, pink, brown, and rust. More colors may develop as this coral is aquacultured. The colors of the Merulina genus can be bright or pale pink, brown, green, cream, violet, lavender, and blue. Some colonies can posses several of these colors.
Merulina Coral Life Cycles: All of the Merulina growth forms can be altered by the environment they are found in. They can grow over 3 feet (100 cm), but it is unknown how long they live.
Difficulty of Care
Merulina Coral Care: The M. amphiata is very difficult to keep in captivity. They need to be far away from any other corals. They also need very strong lighting and specific water flow to keep the surface clear of debris and algae. The water flow requirement has not been quite figured out yet, but moderate flow has been suggested.
Foods / Feeding
Merulina Coral Feeding: In the wild, Merulina corals have developed several feeding strategies. Through a symbiotic relationship with a marine algae, known as zooxanthellae, they receive the majority of their nutrients. They also capture planktonic organisms and microscopic food particles from the water column and can absorb dissolved organic matter.
In captivity, they do well in well-feed reef tanks, accepting very fine particulate foods. Like other SPS, they feed from the water column and use their zooxanthellae. They can be fed microplankton and brine shrimp twice a week.
Pristine tank conditions are typically needed to keep all SPS corals. Keep the nitrate levels low, and maintaining calcium and alkalinity levels. What this particular group of corals needs is unknown. Typically you can do water changes of 20% to 30% a month, 15% every 2 weeks, or 5% a week for SPS corals. However, the Merulina genus doesn’t adjust well to changing conditions so the 5%, less water changed more often, may be best. The 5% a week also seems to really make a big difference in other SPS corals health.
The following water supplements are suggested for Merulina species:
- Calcium: 385 to 425 ppm. If a small poly stony (SPS) coral does not have enough calcium, it will not grow.
- Alkalinity: 3.2 TO 4.8 MEQ/L (8 to 12 dKh)
- Phosphates: 0, zero. Phosphates are the worst of all and all corals hate them.
- Magnesium: 1350-1500. Magnesium makes calcium available, so if your calcium is low, check your magnesium levels before adding any more calcium.
- Strontium: Strontium (10 for most SPS Corals), and trace Elements are also suggested.
A well-feed live rock/reef environment is what is needed for your Ruffled Coral. A mature tank is recommended. Keep the substrate off the corals and provide a refugium to produce natural foods. Most SPS corals do well with some fish for organic matter production.
|Quick Reference Chart|
For tanks with metal halides, you would position SPS corals in the mid levels. With other lighting, position SPS corals at the upper to mid levels depending on the watts used. SPS corals will show whether they are happy or not by the coloring. Make sure that no other corals or even algae can come in contact with your Merulina. Merulina spp. are mild mannered and will end up loosing any chemical warfare.
- Minimum Tank Size / Length: 10 gallons (38 L) or larger
- Marine Lighting: Very high
- Temperature: 73° – 81° F (23° – 27° C)
- Salinity / Specific Gravity: 1.023 – 1.025
- Water Movement: Unknown, but moderate/turbulent is suggested
- Water Region: Middle of the aquarium
Compatibility and Social Behaviors
Merulina are not aggressive corals, nor do they posses strong defenses. Because of this, they must be placed away from any aggressive or defensive coral. The Merulina genus should probably be kept in a species specific environment.
These SPS corals will be easily out competed by any other coral for space. The tissue of the Merulina genus is easily irritated. Do not house sand sifting gobies since getting any substrate on the coral’s surface will generally result in necrosis, and eventually may succumb to RTN. Keep crabs or anything else that likes to sit on corals off of of these corals.
Sex – Sexual differences
Breeding and Reproduction
The small polyp stony (SPS) corals are male and female 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. SPS corals reproduce asexually as well. In the wild SPS corals spread from breakage due to storms and fragmentation.
Merulina corals have not yet been propagated in captivity. For most SPS species, you need to first choose a healthy coral that is not showing any signs of distress. Then, simply cut a branch at least 2″ long and glue the frag to a plug or rock. You can use the 2-part epoxy or underwater putties. A little tip, don’t glue frags upright since they will grow faster on their sides.The slime that the coral will exude should not come in contact with any other corals and gloves are suggested. Give the frag ample water flow.
- Animal-World References: Marine and Reef
- Eric Borneman, Aquarium Corals : Selection, Husbandry, and Natural History , TFH Publications, 2001
- J.E.N. Veron, Corals of Australia and the Indo-Pacific , University of Hawaii Press; 2 Rev Ed edition, 1993
- Bob Goemans, Ruffle/Ridge Coral, Merulina ampliata, Animal Library, Saltwatercorner.com