The beauty of the Bullseye Mushroom or Tonga Blue Mushroom makes it one of the most striking of the Elephant Ear Corals. It has a very colorful appearance, with tentacles that are more like clusters than individual single tentacles.
The various colors within their body include purple, with green margins and highlights as well as multicolored green, red, and blue with some having a red mouth. These contrasting colors are found in the tentacles, tentacle tips, mouth and body color. The area around the oral disc is bare, thus making it an easy species to identify.
The Bull’s Eye Mushroom does not pose a threat to your fish like other Rhodactis, making it great for a great nano tank that has small fish. Only getting to a maximum of 3″ (8 cm) makes this Rhodactis a favorite for those who have smaller quarters and who need a less demanding mushroom.
The Rhodactis inchoata is easy to care for but only likes dim to moderate 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. As far as water movement, they cannot handle high water flow, and prefer low velocities. They can be fed small particles of foods like Cyclo-peeze, daphnia and may occasionally accept very small pieces of fish and crustacean flesh. They are not as needy as other Rhodactis species when it comes to regular feedings.
The R. inchoata is 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.
Bullseye Mushroom, Rhodactis inchoata
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Small red and green specimen
The Bullseye Mushroom is probably the most sought after mushroom coral due to its variable coloring and harmless nature when it comes to fish. Yeah, we have all heard the stories of someone’s large mushroom eating a fish! Well, the Bullseye Mushroom Coral will not be guilty of such an action and are great for nano tanks with nano sized fish! They are tolerate of less than pristine water conditions and are great for beginners!
Bullseye Mushroom, Rhodactis inchoata
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Green Bullseye Mushroom eating
The Bullseye Mushroom is easy to care for and prefers dim to moderate light. Water flow should be low enough so they can catch the food they are being offered. As you see in the video, the water around the mushroom is very low, allowing the Bullseye to close around the food. Typically they only grow to 2″ so they are a great nano tank coral.
Species: Rhodactis inchoata
Distribution / Background
Mushroom Coral Information: The Bullseye Mushroom Rhodactis inchoata was described by Carlgreni in 1943. Some names they are known for are Tonga Blue Mushroom, Elephant Ear Mushroom, Tonga Mushroom, Hairy Mushroom, Bull’s Eye Mushroom, Metallic Mushroom, Mushroom Anemone, and Hairy Mushroom Anemone.
Where Mushroom Corals Are Found: The Rhodactis inchoata are found in the Central Indo-Pacific Ocean.
Mushroom Coral Habitat: These Hairy Mushrooms are found in bays, lagoons, boat channels, reef slopes and reef shallows. They like to grow on dead corals, rubble, and between coral heads. They feed on larger particles in the water column that get trapped on their mucous surface. Predators are unknown.
The Rhodactis inchoata is not on the IUCN Red List for endangered species
What do Mushroom Corals look like: These Coral Mushrooms Rhodactis inchoata 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. inchoata has a surface that is covered with many small clusters of tentacles that give it a unique appearance. The area around the oral disc is bare, thus making it an easy species to identify. The various colors within their body include purple, with green margins and highlights as well as multicolored green, red, and blue with some having a red mouth. These contrasting colors are found in the tentacles, tentacle tips, mouth and body color.
They 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 Bull’s Eye Mushroom can grow from 1.5 – 3″ (4 – 8 cm), but their life span is unknown.
Difficulty of Care
Mushroom Coral Care: The Bullseye Mushroom is easy to care for but only likes dim to moderate light. If the lighting is not their liking, they will fail to thrive and/or shrink. Changing their position will help if they are not doing well. Changing their position will help if they are not doing well. They also cannot handle high water flow, and prefer low velocities.
Foods / Feeding
Mushroom Coral Feeding: The Bullseye Mushroom is a carnivore. In the wild, these corallimorphs feed on larger particles in the water column that get trapped on the mucous surface. In captivity you can feed your R. inchoata small particles of foods like Cyclo-peeze, daphnia and may occasionally accept very small pieces of fish and crustacean flesh. Feed as often as they will close up around it and eat. They do not eat as much as other Rhodactis.
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. inchoata 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 Bull’s Eye 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: 3 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
- Water Region: Bottom of the aquarium
Compatibility and Social Behaviors
The Bullseye Mushroom or Tonga 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. inchoata 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 R. inchoata 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. inchoata 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 Bullseye Mushroom, Hairy Mushroom, Lavender Mushroom or Elephant Ear Mushroom R. inchoata can be found easily online and at pet stores, as well as from frag farmers and most reef clubs. Online they start at about $34.00 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, Elephant Ear Mushroom Coral, Rhodactis inchoata, Animal Library, Saltwatercorner.com
Featured Image Credit: Scheibenanemone2 by User:Haplochromis, Wikimedia Commons Public Domain