The Bubble Coral is a large polyp stony (LPS) coral and is also referred to as a Grape Coral, Small Bubble Coral, or Octobubble. Its genus name,Physogyra, comes from the Latin wordsphysa(air bubble) andgyros(wide circle), which describes its retractable, circular, bubble-shaped polyps. Its polyps are white to tan or green and look like a cluster of grapes or balloons with pointed tips when open during the day.
Its behavior is aggressive and will use its long sweeper tentacles to sting corals that are placed in close proximity to it. It can also sting the reef aquarist who tries to handle it while its sweeper tentacles are out, so precautions should be taken when doing maintenance in the tank. The Bubble Coral requires moderate lighting combined with low water movement within the aquarium. For continued good health, it will also require the addition of calcium, strontium, and other trace elements to the water.
It will also benefit from additional feedings fed weekly in the form of brine shrimp or micro-plankton.