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Get those cool purple and blue colors into your tank with this larger sized Actinodiscus, the Metallic Mushroom Coral!

The Metallic Blue Mushroom Actinodiscus coerulea is also known as the Blue Mushroom or Purple Mushroom. it is very hardy and will multiply on its own, offering you many new mushrooms. True to their names, these striking beauties can be purple, blue or a combination of the two, and may have a white mouth.

Like most Actinodiscus mushrooms, the Blue Mushroom or Purple Mushroom typically reaches only 2-3″ (5-8 cm). They have a pimpled surface which holds toxic stinging cells, instead of the long feeder tentacles found in sea anemones and stony corals. They have no ribbing but they can have ruffled edges.

The A. coerulea is readily available, and a great coral for beginners to advanced aquarists. They will be happy in low to moderate lighting, and their coloring is incredible. In nature they primarily feed off suspended micro particles from the water column. There is no need to feed them in captivity as they will take what nutrients they need from the water. The ruffled edges make them almost look flower like, and they are a great addition to any nano tank, all the way up to, well, whatever size tank you have.

The Blue Mushroom or Purple Mushroom propagates easily in captivity, though after splitting the clone mushroom doesn’t necessarily always resemble the “mother” mushroom. They are semi-aggressive if they are near another coral. They will cause other corals to loose tissue, recess, and possibly die. Acroporas will not grow in aquariums with large mushroom populations. A. coerulea have very few predators if any.

Metallic Blue Mushroom, Actinodiscus nummiforme var. coerulea

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A colony with various textures

The Metallic Blue Mushroom, while referred to as, Actinodiscus coerulea, is actually just a color morph of the so-called Purple Mushroom with the accepted name Actinodiscus nummiforme. As you can see in the video, although they are all blue, there are stripes and pimpled surfaces. Since A. nummiforme is highly variable; ranging from blues, greens, reds, purples and browns, which can be spotted, striped or solid, as well as smooth, fuzzy or bumpy, depending on water nutrients and lighting; one colony can have a high variation within it. Their ruffled edges, small 2 to 3″ size, and ability to form different colors from one parent make them a must have for nano tanks!

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Scientific name

Family: Discosomatidae

Species: Actinodiscus coerulea

Distribution / Background

Mushroom Coral Information: The Metallic Blue Mushroom Actinodiscus coerulea was discovered by Ruppell and Leuckart in 1828. Some names they are known for are Blue Mushroom, Purple Mushroom, Metallic Mushroom Coral, Disc Anemones, Mushroom Anemones, Mushroom Corals, and just plain Mushrooms.

As far as current taxonomy, the A. coerulea is listed under Actinodiscus and not Discosoma, according to the 2007 taxonomy list. The taxonomical identification of mushroom corals has a history of limited and dated information which is often of dubious value and sometimes incorrect. Mushrooms corals have no fossil records and studying the physical aspects has proved to be not very reliable for identification. Modern methods using DNA and RNA testing to deduce the sequence of genes, though more reliable, is not readily available.

Where Mushroom Corals Are Found: The Actinodiscus coerulea are found in pretty much all of the reefs in the Indo-Pacific Ocean, from East Africa to the Central Pacific Ocean.

Mushroom Coral Habitat: The Blue Mushrooms or Purple Mushrooms are found in low current, mid-depth waters like tide pools and shallow lagoons. They like to grow on dead corals, rubble, and between coral heads. They feed off micro particulate foods in the water column. A. coerulea propagates easily in captivity, which can contribute to preserving the wild populations. Even after splitting, 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.

Status

The Actinodiscus coerulea is not on the IUCN Red List for endangered species

Description

What do Mushroom Corals look like: These Coral Mushrooms Actinodiscus coerulea 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 A. coerulea can be purple, blue and a combo of the two and may have a white mouth. They have a pimpled surface which holds toxic stinging cells, instead of the long feeder tentacles found in sea anemones and stony corals. They have no ribbing but they can have ruffled edges.

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

Difficulty of Care

Mushroom Coral Care: The Blue Mushroom or Purple Mushroom is easy to care for and does not like or need high levels of light. They should be kept in shaded areas in tanks with high output lamps. If they are not shaded, they turn all brown and fail to thrive. Some will just float around the tank until they find a nice shaded area or have an unpleasant encounter with a pump. They also cannot handle high or high to moderate water flow. But they can handle higher levels of nitrate than SPS and LPS corals.

Foods / Feeding

Mushroom Coral Feeding: The Blue Mushroom or Purple Mushroom is a carnivore. In the wild, these corallimorphs are well equipped with nutritional alternatives for their well-being. They derive nutrition from their symbiotic algae, zooxanthellae, that dwells within their tissues and they eat suspended micro particles out of the water column. They can 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 A. coerulea newly hatched artemia once in a great while. But really, it is the nutrient level in your tank that they will thrive in, and not direct feedings.

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 A. coerulea need nutrients to survive on and will not do well in a pristine environment.

Aquarium Parameters

A typical live rock/reef environment is what is needed for your Blue 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. Place in the middle level for weaker lighting and at the bottom for moderate lighting.
  • Temperature: 72° – 83° F (22° – 28° C)
  • Salinity / Specific Gravity: 1.023 to 1.025
  • Water Movement: Low / weak
  • Water Region: Middle to bottom of the aquarium

Compatibility and Social Behaviors

The Blue Mushroom or Purple 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 A. coerulea 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 A. coerulea 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 A. coerulea 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 Metallic Blue Mushroom, Blue Mushroom, or Purple Mushroom A. coerulea can be found easily online and at pet stores, as well as from frag farmers and most reef clubs. Online they are $44.00 or more depending on the size of rock they are on, and the color.

References