Elephant Ear Mushroom
Elephant's Ear MushroomRhodactis mussoidesPhoto © Animal-World: Courtesy David Brough
With its large and sometimes folded oral disc, the Elephant Ear Mushroom resembles the shape of an elephant ear!
The Elephant Ear Mushroom is one of the larger members of the Rhodactis genus. If you have a large aquarium, this mushroom coral is a great addition. With its leafy appearance and reaching up to 15" (40 cm) or so in diameter, it will neatly fill up the space and provide you with an impressive showpiece.
The color of the Rhodactis mussoides is usually green or brown. It has short tentacles that are arranged radially and it has multiple mouths. It has a surface that is large and wavy with a leathery texture. Instead of long feeder tentacles, they will form rounded vesicles, and these do have toxins in them like all other mushroom corals. Be cautious with small tank mates. They can feed on small fish and crustaceans by luring them into their partially closed "purse-string" or balloon like enclosure. Seeking what looks like good shelter, once the prey are inside, the Rhodactis will just close up and consume them.
The Elephant Ear Mushroom not only looks spectacular, but is easy to care for and easy to find in a fish store or online. The Elephant's Ear Mushroom prefers low to moderate lighting. If the lighting is not their liking, they will fail to thrive and/or shrink. They can easily be brought back by changing their position in the water and by extra feedings. As far as water movement, they prefer low water velocity, but will do okay in a moderate flow as well.
The R. mussoides are bred in captivity and they are very easy to propagate in any home aquaria, which can contribute to preserving the wild populations. Even after splitting, the clone mushroom at times doesn't always resemble the "mother" mushroom. Predators are unknown.
Species: Rhodactis mussoides
Mushroom Coral Information: The Elephant Ear Mushroom Rhodactis mussoides was described by Saville-Kent, 1893. Some names they are known for are Elephant's Ear Mushroom, Hairy Mushroom, Metallic Mushroom, Mushroom Anemone, and Hairy Mushroom Anemone.
Where Mushroom Corals Are Found: The Rhodactis mussoides are found in the Central Indo-Pacific Ocean.
Mushroom Coral Habitat: These Hairy Mushrooms are found singly in sediment substrate lagoons and on shallow reefs. They like to grow on dead corals, rubble, and between coral heads. They feed on larger particles from the water column that are trapped on their mucous laden surface when fully open. They can also feed on small fish and crustaceans by luring them into their partially closed "purse-string" or balloon like enclosure. Seeking what looks like good shelter, once the prey are inside, the Rhodactis will just close up and consume them. Predators are unknown.
The Rhodactis mussoides is not on the IUCN Red List for endangered species
What do Mushroom Corals look like: These Coral Mushrooms Rhodactis mussoides are basically a coral without a skeleton and their internal structures are the same as stony corals. The top of their body or the upper surface is called the oral disc. The stalk area, which is very small, is called the column and it is located just above the pedal disc, which is where they attach to surfaces. On their surface, they have short feeding tentacles to capture prey that hold several types of stinging cells.
The R. mussoides has a wavy, leathery surface with short,tentacles arranged radially, and they can have several mouths. Their colors are usually green or brown. At times they will make a trumpet shape which is thought to be formed when needing nourishment or if the light level is low or low quality due to age. With this shape they have formed, fish will be fooled into taking shelter in that little "cave" only to become a meal for the mushroom.
Mushroom Coral Life Cycles: The Elephant Ear Mushroom can grow to 10" (40 cm), but their life span is unknown.
Mushroom Coral Care: The Elephant Ear Mushroom is easy to care for. This mushroom likes low to moderate levels of light. If the lighting is not their liking, they will fail to thrive and/or shrink. They can easily be brought back by changing their position in the water and by extra feedings. They also cannot handle too high a water flow since it will prevent them from getting nourishment.
Mushroom Coral Feeding: The Elephant Ear Mushroom is a carnivore. In the wild, these corallimorphs feed on larger particles from the water column are trapped on the mucous laden surface when fully open, and then consumed. They can also feed on small fish and crustaceans by luring them into their partially closed "purse-string" or balloon like enclosure. Seeking what looks like good shelter, once the prey are inside, the Rhodactis will just close up and consume them.
Like most mushroom corals, they are also well equipped with nutritional alternatives for their well-being. They can derive nutrition from their symbiotic algae, zooxanthellae, that dwells within their tissues. They can also actually warp their surfaces to change the water flow over them to direct particulate and flocculent material toward their mucous center for absorption.
In captivity you can feed your R. mussoides small pieces of fish and crustacean flesh. Make sure they are located where the water velocity is low. You will know when the water is too quick because the food will be whisked away before they have a chance to close around it.
Water changes of 10% bi-monthly or 20% a month are typical. Provide a reef environment with proper magnesium levels. Some claim proper iodine levels are beneficial also. Due to their toxins, active carbon is a good idea with larger colonies of mushrooms. Do not over skim since the R. mussoides need nutrients to survive on and will not do well in a pristine environment.
A typical live rock/reef environment is what is needed for your Elephant Ear Mushroom. Provide rubble or dead coral and live rock for them to have something with which to attach their pedal disc. They do not do well with strong water movement, so direct the power heads and intake nozzles away from them. As they can float around when looking for a place to settle, it's a good rule of thumb to have all of your pumps covered. Most good quality pumps have guards on them.
- Minimum Tank Size / Length: 20 gallons or more
- Marine Lighting: Low to moderate
- Temperature: 72° - 83° F (22° - 28° C)
- Salinity / Specific Gravity: 1.023 to 1.025
- Water Movement: Low / weak to moderate
- Water Region: MIddle to bottom of the aquarium
The Elephant Ear Mushroom is semi-aggressive if they are near another coral. They will cause other corals to loose tissue, recess possibly die. Acroporas will not grow in aquariums with large mushroom populations. Make sure to leave 6 - 8 " between your mushrooms and other corals. Watch the growth rate since the R. mussoides will overgrow and kill any nearby corals. Small slow moving fish and shrimp run a risk of being consumed by the R. mussoides.
Mushroom Anemones will tolerate their own species and usually other Mushrooms. In the wild many species of Mushroom Corals occur together in large groups. In captivity R. mussoides will get along with their own species, but may not tolerate mushroom species outside their colony. Even in one genus, if the color is different or a different species, the weaker mushroom will detach and find another location. Strong water movement will cause them to detach as well.
No sexual difference in appearance is known.
- Mushroom Coral Reproduction:
Corallimorphs reproduce in 4 different ways. The first three ways, asexual budding, laceration, and division/fission, are successful in the aquarium as most hobbyists soon discover. Budding is where individuals are formed from particles divided off from the pedal disc. Similar to budding, laceration happens when they move slowly over the surface and leave behind small pieces that will eventually form into mushrooms. Division or fission is where an individual divides down the center and forms two animals.
Sexual reproduction is where eggs and sperm are released into the water column. They unite and form free-swimming larvae which are initially plankonic, and them settle and adhere to the substrate. Sexual reproduction has not been well documented, and has not been observed in captivity. Presumably modern filtration methods are inhospitable to free swimming larvae.
- Mushroom Coral Propagation:
Mushroom corals can be easily propagated in captivity by cutting individual polyps into several pieces. Placed the pieces on a gravel substrate with low water flow. They will attach themselves to pieces of gravel. Later they can then be super glued to a suitable substrate such as a reef plug. It has been stated that the warmer end of their temperature spectrum encourages reproduction.
For details on how to propagate your mushroom corals see Mushroom Corals: Mushroom Coral Propagation
The R. mussoides are disease resistant, and only affected by improper husbandry. Problems for the most Corallimorphs are pretty minimal unless your lighting, water movement, feeding and water quality are improper for these animals. A sign of this is if your coral mushroom detaches to look for "better conditions" to settle in. They have very few predators if any.
Mushroom Corals for Sale: The Elephant Ear Mushroom, R. mussoides can be found easily online and at pet stores, as well as from frag farmers and most reef clubs. Online they start at about $38.00 USD and up, depending on the size.
- Animal-World References: Marine and Reef
- Eric Borneman, Aquarium Corals : Selection, Husbandry, and Natural History , TFH Publications, 2001
- Anthony Calfo, Book of Coral Propagation, Volume 1 Edition 2: Reef Gardening for Aquarists, Reading Trees; 2 edition, 2007
- Ronald L. Shimek, Guide to Marine Invertebrates: 500+ Essential-to-Know Aquarium Species, Microcosm, 2005
- Julian Sprung, Aquarium Invertebrates, Advanced Aquarist's Online Magazine, Copyright 2002
- Bob Goemans, Elephant Ear Mushroom, Rhodactis indosinensis, Animal Library, Saltwatercorner.com