Rhodactis

Rhodactis is a genus of coral belonging to the family Fungiidae, commonly known as mushroom corals. These corals are characterized by their distinctive mushroom-shaped appearance, with a broad, flat oral disc and a short, stalk-like column. They are found in a variety of habitats, including reefs, lagoons, and seagrass beds, in tropical and subtropical waters of the Indo-Pacific region.

Common Names

Common names for Rhodactis corals include:

  • Mushroom coral
  • Disk coral
  • Plate coral

Characteristics

Rhodactis corals are characterized by the following features:

  • Mushroom-shaped morphology: They possess a broad, flat oral disc with a short, stalk-like column.
  • Solitary growth habit: They typically live as individual polyps, not forming colonies.
  • Symbiotic relationship with zooxanthellae: Like most reef-building corals, Rhodactis corals host symbiotic algae called zooxanthellae, which provide them with nutrients through photosynthesis.
  • Variety of colors: They come in a range of colors, including brown, green, orange, and red.
  • Extensive oral disc: The oral disc can be quite large, sometimes exceeding 10 centimeters in diameter.
  • Contractile tentacles: They have numerous tentacles that can be retracted into the oral disc.

Environments

Rhodactis corals are found in a variety of environments, including:

  • Reefs: They can be found on both shallow and deeper reefs.
  • Lagoons: They are commonly found in lagoons with clear, calm waters.
  • Seagrass beds: Some species of Rhodactis can be found in seagrass beds.
    • They prefer environments with:

    • Moderate to high light levels: They need sufficient light for their symbiotic algae to photosynthesize.
    • Moderate water currents: They require some water movement to deliver food and oxygen.
    • Stable salinity: They are sensitive to changes in salinity.

References

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