Let's Go Disco

One of the most common questions for new aquarists is some variation of “I want to start keeping corals, where should I start?” If you ask this of 50 different experienced mini-reef keepers, you'll likely get 50 different answers, and you may even get different answers from the same aquarist on different days. Whatever the day, and whoever the aquarist, one of the best answers for this question is Mushroom Polyps and more specifically, Discosoma / Actinodiscus Mushrooms. Interestingly, they aren't actually a true coral, but rather a corallimorph. For many years the nomenclature between Actinodiscus and Discosoma was regional, with Discosoma being Caribbean, and pretty much everything else being Actinodiscus. Most (if not all) of the species we commonly see in the aquarium hobby have been officially retagged as Actinodiscus regardless of origin. While many corals can be finicky or straight up difficult to keep, Actinodiscus are not. They are very tolerant of a wide variety of conditions, often thriving in conditions that would send your hardiest stony corals into an early grave. Elevated nutrient levels, low lighting and low flow are the bane of nearly all aquariums systems, but not so for these mushrooms. In fact, these very conditions are frequently intentionally maintained to make the mushroom corals reproduce (a process called “budding.”) They are also some of the most colorful sessile invertebrates commonly sold for aquariums (sessile basically means “not mobile.”) In the wild, they are commonly found in areas of siltation, low flow, and mucky sites, though they are also found tucked into low light areas like the nooks and crannies of cleaner, brighter reef environments. We have found that these corallimorphs can be adapted to higher light conditions, though there is a limit to this. At full reef lighting, they seem to more frequently detach, and develop growths on their faces. The only other common aquarium environmental aspect that they do poorly with is high flow, which commonly makes them detach from substrate and they do not reattach quickly or easily. There is a myriad of colors to choose from, brilliant neon green, deep ruby reds, azure ocean blue and deep royal purples. Some Actinodiscus will have interesting patterns of mixed color (though these do tend to be on the pricey side). Not only are they wildly colorful, they have a tendency toward being colorfast. While many corals will brown out very easily, Actinodiscus will generally keep their color, and sometimes gain interesting new coloration and patterning in the aquarium as long as a couple simple things are paid attention to. One is to keep them away from other aquarium inhabitants that could sting or harass them. The other is to be wary of chemical competition in the aquarium. Either utilize some form of chemical filtration like activated carbon to keep the corals from any kind of chemical warfare, or utilize only mushrooms from the Actinodiscus/Discosoma genus. What we have found over time is that the fewer species you keep, the brighter color they usually maintain. Mushroom corals from this genus are not aggressive feeders; target feeding even small meaty foods is generally very ineffective. They do well with amino acid supplements, though we do not believe these to be strictly necessary, and amino acid dosing should be done with extreme judiciousness as it can also fuel algal, diatom and cyanobacteria blooms. Actinodiscus seem to benefit from dosing Nutramar's line of Micro Algae products. Some scientists have recently indicated that some of the metabolic needs of the mushroom coral may come from bacterial flocculents and other finer foods. This seems to make sense with our personal experiences dosing the microalgae. For the new hobbyist there are few better invertebrates to try than the Actinodiscus genus, and for the experienced hobbyists, we believe the same is true. They offer gorgeous color and movement, are hardy and colorfast, are consistently available both wild and aquacultured and adaptable to a huge range of aquariums. What is not to love?

Ref:

https://www.nature.com/articles/nbt1037

https://www.qualitymarine.com/news/discosoma-sp-mushroom-polyps/