The Discosoma howesii – Syn: Rhodactis howesii – is most commonly known as the Green Fuzzy Mushroom or Elephant Ear Mushroom Coral. It is also known as the Giant Anemone, Giant Mushroom Anemone, Giant Cup Mushroom, and Giant Anemone. According to the 2007 Taxonomy List, this corallimorph is listed as D. howesii as well as Rhodactis howesii. Due to the primary category of Discosoma, we have put it here until this coral obtains a definite genus location.
The Elephant Ear Mushroom Coral is another mushroom with that “fuzzy” look. It makes a great addition to a collection of smooth mushrooms, giving an added texture to the tank. And it is not as dangerous to slow moving fish as some of the other mushrooms with that same textured look.
The Green Fuzzy Mushroom or Elephant Ear Mushroom only grows to 2-3″ (5-8 cm), so is great for any nano tank, or any larger sized aquarium as well. It usually comes in green or brown. The tentacles are generally fuzzy and/or knobby instead of the long feeder tentacles found in sea anemones and stony corals. Yet they still have toxic stinging cells which helps to move other corals away from their growing colonies.
This mushroom is hardy and easy to care for. However it is a more obscure corallimorph, which make specimens difficult to acquire. They are also a bit more difficult than the Actinodiscus genus to care for because they are not as tolerant of poor water conditions. They cannot handle a high water flow since it will prevent them from getting nourishment. These corallimorphs also grow faster than their Caribbean cousins.
Finding what seems to be the only Discosoma howesii on you tube, alas, its a floater. This does not appear to be a hairy mushroom since the tentacles are not dense enough. If the identity is wrong, this video still gives a valuable opportunity to show what happens when your mushroom coral is not happy. It can be a lighting issue, flow, water quality or it is being chemically chased off by another mushroom. This floater seems to match the description of a D. howesii, having spaced fuzzy and thin tentacles, very short foot and the color is right on the money!
Species: Discosoma howesii Syn: Rhodactis howesii
Distribution / Background
Mushroom Coral Information: The Green Fuzzy Mushroom Discosoma howesii or Rhodactis howesii was discovered by Saville and Kent in 1893. According to the 2007 Taxonomy List, this mushroom coral is currently shown in both the Discosoma and Rhodactis genus. Due to the primary category of Discosoma, we have put it here until this coral obtains a definite genus location.
Some names they are known for are Elephant Ear Mushroom Coral, Giant Anemone, Giant Mushroom Anemone, Giant Cup Mushroom, and Metallic Mushroom. General names all Corallimorphs are called include Mushroom Coral, False Coral, Disk Anemone, Mushroom Anemone, Coral-like Anemone, False Anemone, and Jewel Anemone.
Where Mushroom Corals Are Found: The Discosoma howesii are found in the Central Indo-Pacific Ocean.
Mushroom Coral Habitat: These coral mushrooms are found on reef shallows, bays, lagoons, boat channels and reef slopes. They like to grow on dead corals, rubble, and between coral heads. They feed off micro particulate items in the water column although under very low water movement can grab larger particles as well. The D. howesii propagates easily in captivity, which can contribute to preserving the wild populations. Yet after splitting, the clone mushroom doesn’t necessarily always resemble the “mother” mushroom. They have very few predators if any. These grow faster than their Caribbean cousins.
The Discosoma howesii is not on the IUCN Red List for endangered species
What do Mushroom Corals look like: These Coral Mushrooms Discosoma howesii 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.
The Green Fuzzy Mushroom comes in green or brown. The tentacles are generally fuzzy and/or knobby instead of long feeder tentacles, yet they still have toxins which help to move other corals away from their growing colonies.
Mushroom corals can actually warp the surface of their oral disc to change the water flow over them to direct particulate and flocculent material toward their mucous center for absorption. At times they will make a trumpet shape. This is thought to be formed when they are needing nourishment, or if the light level is low, or is of low quality due to age.
Mushroom Coral Life Cycles: The Green Fuzzy Mushroom can grow to 2-3″ (5-8 cm), but their life span is unknown.
Difficulty of Care
Mushroom Coral Care: The Green Fuzzy Mushroom is easy to care for. It does not like or need very high levels of light, although can tolerate more light than some mushrooms. They should be kept in areas of indirect light in tanks with high output lamps like Metal Halides. Otherwise they turn all brown and fail to thrive, or will just float around the tank until they find a suitable spot. They cannot handle high water flow since it will prevent them from getting nourishment. They are not as tolerant to poor water conditions as the Actinodiscus genus.
Foods / Feeding
Mushroom Coral Feeding: The Green Fuzzy Mushroom is a carnivore. In the wild, these corallimorphs eat suspended micro particles out of the water column and at times small particles of food. Most mushroom corals 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 the D. howesii can be fed newly hatched artemia, Cyclo-peeze, and even flake and mysis shrimp if the water velocity is very 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 D. howesii need nutrients to survive on and will not do well in a pristine environment. However, they are not as tolerant to poor water conditions as the Actinodiscus genus.
A typical live rock/reef environment is what is needed for your Green Fuzzy 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:Nano tank of 1 gallon or more
- Marine Lighting: Indirect, low to moderate
- 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 Green Fuzzy 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 D. howesii will overgrow and kill any nearby corals.
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 D. howesii 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 D. howesii 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 Green Fuzzy Mushroom D. howesii, also known as the Elephant Ear Mushroom Coral, cannot be found easily online or in pet stores, although you may be able to special order them.
- 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 Coral, Rhodactis howesii, Animal Library, Saltwatercorner.com
Featured Image Credit: PAUL ATKINSON, Shutterstock