Orange Cup Coral

Overview

The Orange Cup Coral is a non-reef-building stony coral known for its vibrant, sun-like appearance and its ability to thrive in environments where other corals cannot. Unlike most tropical corals, it lacks symbiotic zooxanthellae, allowing it to inhabit dark, shaded areas such as caves, shipwrecks, and deep-water structures.

Distribution & habitat

Native to the Indo-Pacific and Red Sea, this species has become a successful invasive organism in the Atlantic Ocean, Caribbean, and Gulf of Mexico. It frequently colonizes artificial structures like oil platforms and ship hulls, often spreading via ballast water or by clinging to vessels. It prefers nutrient-rich waters and can be found from shallow subtidal zones down to depths of 130 meters.

Appearance

This coral forms rounded, semi-spherical colonies with a white or light-colored skeleton. The polyps, which feature bright orange to yellow tentacles, are typically retracted during the day and extend at night to feed. The individual calices are cup-shaped and generally measure about 1 centimeter in diameter.

Biology & behavior

As an ahermatypic (non-reef-building) coral, it does not rely on photosynthesis. It is a heterotrophic species that depends entirely on capturing food from the water column. It is known for its resilience and ability to withstand conditions that might cause bleaching or mortality in other coral species.

Feeding

This coral is an active nocturnal feeder. It uses stinging cells located on its tentacles to capture zooplankton from the surrounding water.

Reproduction

This species reproduces both sexually and asexually. It is a gonochoristic (separate sexes) brooder, where females capture sperm released by males into the water column. Fertilization and larval development occur within the female, which later releases free-swimming larvae that can disperse over long distances before settling on a suitable substrate.