Mushrooms

Mushroom corals are soft-bodied colonial cnidarians commonly kept in reef aquariums for their coloration, hardiness, and adaptability. Although often grouped with soft corals in the reef hobby, mushroom corals belong primarily to the order Corallimorpharia and do not produce a hard calcium carbonate skeleton.

Mushroom corals consist of a fleshy oral disc attached to rock or substrate by a small pedal foot. Many species reproduce readily through splitting, budding, or tissue fragmentation, allowing colonies to spread across rockwork over time. Their appearance can vary greatly depending on the species, ranging from smooth and flat discs to textured, hairy, or bubble-covered surfaces.

Common mushroom groups found in reef aquariums include Discosoma, Rhodactis, and Ricordea. Different species and morphs may vary considerably in size, texture, coloration, and environmental preference.

Most mushroom corals thrive in stable reef conditions with temperatures between 76–79°F, salinity around 1.025–1.026 specific gravity, and a pH between 8.0–8.4. Alkalinity is commonly maintained between 7.5–9 dKH, calcium around 380–450 ppm, and magnesium between 1250–1400 ppm. While mushroom corals do not build rigid skeletons, stable water chemistry still supports healthy tissue growth and overall system stability.

Mushroom corals generally tolerate and often prefer slightly elevated nutrient levels compared to many SPS corals. Nitrate levels around 5–20 ppm and phosphate levels between 0.03–0.15 ppm are commonly acceptable for many species. Extremely nutrient-poor systems may lead to reduced growth, fading coloration, or failure to fully expand.

Most mushroom corals prefer low-to-moderate indirect flow. Proper flow helps keep debris from settling on the coral while allowing the tissue to remain inflated and expanded. Healthy mushrooms typically display full expansion, consistent coloration, and a firm attachment to rockwork under appropriate conditions.

Excessive flow may cause mushrooms to remain shrunken, detach, or fold inward, while insufficient flow can allow detritus and algae to accumulate on the tissue surface. Lighting requirements vary by species, though many mushroom corals adapt well to low-to-moderate lighting conditions. Excessively intense lighting may cause some species to bleach, shrink, or seek shaded areas within the aquarium.

Although mushroom corals are often considered beginner-friendly, some species can spread aggressively and compete with neighboring corals through direct contact or chemical competition. Careful placement and routine maintenance can help prevent mushrooms from overtaking portions of a reef aquarium.