The Purple Hairy Mushroom is similar to its cousin the Green Hairy Mushroom, but they don’t grow as large!
The Purple Hairy Mushroom is another member of the Rhodactis genus that is easy to care for, easy to find, and moderately priced. They are similar to the Green Hairy Mushroom R. indosinensis, yet different. This can be confusing since both of these mushrooms are often just simply called ‘Hairy Mushrooms’.
The Purple Hairy Mushroom does not grow nearly as large as the Green Hairy Mushroom, which in a nano tank is good news. They also need a lower level of light. Appearance wise, they are also quite different. The R. rhodostoma have much more developed marginal tentacles. Its tentacles are branched and spaced apart, which makes it look like a cauliflower arrangement. It also comes in purple, so this is the species you will probably be getting if it is labeled “Purple Hairy Mushroom” rather than just Hairy Mushroom.
The Rhodactis rhodostoma is easy to care for but needs reduced 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. rhodostoma are bred in captivity and is very easy to propagate in any home aquaria, which can contribute to preserving the wild populations. Just keeping it well fed with small pieces of fish and crustaceans will cause the it to multiply quickly. Even after splitting, the clone mushroom at times doesn’t always resemble the “mother” mushroom. Predators are unknown.
Sometimes called, “Lavender Mushroom,” the Purple Hairy Mushroom is a beautiful Rhodactis which will not typically eat any fish! They are pretty cool, swaying in the current, often hosting a happy clownfish. As you can see, feeding them is not difficult and if you want them to multiply, do that often!
Species: Rhodactis rhodostoma
Distribution / Background
Mushroom Coral Information: The Purple Hairy Mushroom Rhodactis rhodostoma was described by Ehrenberg in 1834. Some names they are known for are Lavender Mushroom, Elephant Ear Mushroom, Hairy Mushroom, Metallic Mushroom, Mushroom Anemone, and Hairy Mushroom Anemone.
Where Mushroom Corals Are Found: The Rhodactis rhodostoma are found in the Central Indo-Pacific Ocean.
Mushroom Coral Habitat: These Hairy Mushrooms are found on reef slopes, reef shallows, bays, lagoons, and boat channels. They like to grow on dead corals, rubble, and between coral heads. They feed on larger particles in the water column, which are trapped on the mucous laden hairy surface when fully open, and then consumed. They can also eat very small fish and tiny crustaceans by luring them into their partially closed “purse-string” like enclosures. 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 rhodostoma is not on the IUCN Red List for endangered species
What do Mushroom Corals look like: These Coral Mushrooms Rhodactis rhodostoma 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. They have a thinner oral disc compared to the Green Hairy Mushroom R. indosinensis, yet does not grow as large.
Courtesy David Brough
The R. rhodostoma has a surface that is covered with short, branched tentacles that are much more developed than other Rhodactis. They are arranged radially, thus making them look like a field of little cauliflower. Their marginal tentacles are well developed too.
The various colors within their body include purple, brownish purple, green, rust or brown. These contrasting colors are found in the tentacles, tentacle tips, mouth and body color. Usually the brown tentacles mushrooms are tipped in contrasting colors and the oral disc may be pink inside.
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 Purple Hairy Mushroom can grow to 5″ (13 cm), but their life span is unknown.
Difficulty of Care
Mushroom Coral Care: The Purple Hairy Mushroom is easy to care for but does not like high levels of light, in fact it prefers reduced 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. They also cannot handle too high a water flow, they can handle moderate but prefer low velocities.
Foods / Feeding
Mushroom Coral Feeding: The Purple Hairy Mushroom is a carnivore. In the wild, these corallimorphs feed on larger particles in the water column, which are trapped on the mucous laden hairy surface when fully open, and then consumed. They can also eat very small fish and tiny crustaceans by luring them into their partially closed “purse-string” like enclosures. 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. rhodostoma small pieces of fish and crustacean flesh. They can also be fed pellet and flake, though these are not suggested on a regular basis. Feed as often as they will close up around the food and eat. The more your feed them, the faster they multiply if that is your aim. If the water is moderate, you may have to hold the food in place until the mushroom gets a chance to close around the food. Hold lightly and do not press into the mushroom.
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. rhodostoma 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 Purple Hairy 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:10 gallons or more
- Marine Lighting: Low
- Temperature: 72Â° – 83Â° F (22Â° – 28Â° C)
- Salinity / Specific Gravity: 1.023 to 1.025
- Water Movement: Low / weak to moderate
- Water Region: MIddle to bottom of the aquarium
Compatibility and Social Behaviors
The Purple Hairy 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. rhodostoma will overgrow and kill any nearby corals.
Slow moving fish and shrimp run a risk of being consumed by the R. rhodostoma. At times, clown fish may adopt a Purple Hairy Mushroom as a host, however these fish can irritate them. If the mushroom remains closed up and small, you must remove the fish to prevent further irritation. Just like anemones, the very large ones may tolerate a clownfish better than small ones.
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. rhodostoma 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.
Sex – Sexual differences
No sexual difference in appearance is known.
Breeding and Reproduction
- 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. rhodostoma 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 Purple Hairy Mushroom, Hairy Mushroom, Lavender Mushroom or Elephant Ear Mushroom R. rhodostoma can be found easily online and at pet stores, as well as from frag farmers and most reef clubs. Online they start at about $36.00 USD and up, depending on the size of the rock they are sold on. Some may sell them individually as well.
- 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, Lime Elephant Ear Mushroom Coral, Rhodactis rhodostoma, Animal Library, Saltwatercorner.com