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The Discosoma carlgreni, most commonly known as the Forked Tentacled Mushroom, is named for its obvious shape. It is also known as the Forked Tentacle Corralimorpharian, Forked Mushroom, and Neon Disc Anemone. It is one of only a few mushroom corals that have kept their genus names consistently.

The Forked Tentacled Mushroom usually comes in solid green or brown, and at times is more colorful with a brown or purple mottling on the surface. The tentacles are generally the same color, but at times, they can be green, brown, white, yellow, or gray. Their tentacles are elongated nubs or knobby tentacles, which are often split. They hold toxins and along the perimeter they are “points” that are spaced, which almost make it look like the mushroom has spikes.

The Forked Tentacled Mushroom is very decorative, inexpensive, and moderate to easy to care for. They are a bit more difficult than the Actinodiscus genus because they are not as tolerant of poor water conditions. D. carlgreni can grow quite to to 2-3″ (5-8 cm), yet they do tend to grow slower than Indo-Pacific Discosoma. They prefer dim light and a low water flow. Too much light and a higher water flow will actually cause them to shrink their size.

The D. carlgreni propagates easily in captivity, which can contribute to preserving the wild populations. After splitting however, the clone mushroom doesn’t necessarily always resemble the “mother” mushroom, thus giving the aquarist a variety of shades and colors. They have very few predators if any.

Forked Tentacle Mushroom, Discosoma carlgreni

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A color variation of this mushroom

The Forked Tentacle Mushroom, like others in the Discosoma genus, can vary in coloring and even texture. What sets this species, D. carlgreni apart, is that is does well in tanks that are 76˚F or LOWER. They are a subtropical mushroom anemone and prefer low to moderate light and water flow. When multiplying, they often can be a different color than the original “mother” mush. While most Discosoma do not carry the toxins that some mushrooms have in their tentacles, this species may be an exception so be careful with slow moving tank mates.

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Scientific name

Family: Discosomatidae

Species: Discosoma carlgreni

Distribution / Background

Mushroom Coral Information: The Forked Tentacled Mushroom Discosoma carlgreni was discovered by Watzi in 1922. Some other names they are known for are Forked Tentacle Corralimorpharian, Neon Disc Anemone, Metallic Mushroom, Forked Mushroom, Elephant Ear Mushroom. General names all Corallamorphs 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 carlgreni are found in the Caribbean and Haiti.

Mushroom Coral Habitat: These coral mushrooms are found in colonies and individually in areas where there is low light. 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. carlgreni tend to grow slower than Indo-Pacific Discosoma. It 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.

Status

The Discosoma carlgreni is not on the IUCN Red List for endangered species

Description

What do Mushroom Corals look like: These Coral Mushrooms Discosoma carlgreni 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 oral disc is raised and rigid. 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.

Forked Tentacled Mushroom usually comes in solid green or brown, and at times is more colorful with a brown or purple mottling on the surface. The tentacles of the D. carlgreni are generally the same color, but at times, they can be green, brown, white, yellow, or gray. Instead of long feeder tentacles, they have elongated nubs or knobby tentacles which are often split and hold toxins. Their perimeter has “points” that are spaced, which almost make it look like the mushroom has spikes.

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 Forked Tentacled Mushroom can grow to 2-3″ (5-8 cm), but their life span is unknown.

Difficulty of Care

Mushroom Coral Care: The Forked Tentacled Mushroom is moderate to easy to care for and does not like or need high levels of light. Too much light and a higher water flow will cause them to shrink their size. They also cannot handle high water flow since it will prevent them from getting nourishment. They should be kept in shaded areas in tanks with high output lamps like Metal Halides. If they are not shaded, they turn all brown and fail to thrive, or will just float around the tank until they find a suitable spot or they have an unpleasant encounter with a pump. They are not as tolerant to poor water conditions as the Actinodiscus genus.

Foods / Feeding

Mushroom Coral Feeding: The Forked Tentacled Mushroom is a carnivore. In the wild, these corallimorphs feed off micro particulate items in the water column although under very low water movement can grab larger particles as well. 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 you can feed your D. carlgreni 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.

Aquarium Care

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. carlgreni 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.

Aquarium Parameters

A typical live rock/reef environment is what is needed for your Forked Tentacled 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: 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

Compatibility and Social Behaviors

The Forked Tentacled Mushroom is semi-aggressive if they are near another coral. They will cause other corals to loose tissue, recess possibly die. Do not keep with slow moving fish or crustaceans as they may become a meal to your D. carlgreni. 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. carlgreni 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. carlgreni 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

Potential Problems

The D. carlgreni 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.

Availability

Mushroom Corals for Sale: The Forked Tentacled Mushroom, Forked Tentacle Corralimorpharian, Neon Disc Anemone, or Forked Mushroom D. carlgreni can be found easily online and at pet stores, as well as from frag farmers and most reef clubs. Online they start at about $9.00 USD for a single polyp, or more depending on if they are sold in a colony or not.

References

Featured Image Credit: Vi – Discosoma carlgreni – 1 by Emőke Dénes, Wikimedia Commons CC SA 4.0 International