Yellow Polyps , Parazoanthus gracilis, are an easy to keep splash of bright yellow color and are a great choice for the beginner reef aquarist. They live on rocks and other surfaces where there is moderate light and water movement. They catch zooplankton from the water column and may also contain the marine algae known as zooxanthellae. These will both provide nutrients that are necessary for their survival. They reproduce by budding and will spread across any surface, including the aquarium glass.
Water Flow and Lighting
They prefer a moderate level of water movement, and a low to moderate lighting level. Lighting can be Power compacts, T5's, LED's or even Metal Halides. Any lighting will work as long as the proper level of light is provided. If a Par meter is available the appropriate lighting level is anywhere from a Par 100 all the way to a Par 250. Which is a wide range of acceptability. For lighting spectrum use between a 14-20K color spectrum for your bulbs for best coloration.
While the sting is not strong, they are semi-aggressive and need to have space between their colony and any neighbors. Placement can be any where in the aquarium as long as it receives adequate water flow and lighting levels and leaves enough room around your corals that they have room for growth without infringing on another corals growing room or lighting.
Diet and Feeding
In captivity the Yellow Polyps do well with crustacean and fish flesh that has been minced, along with worms that are small enough for them to grab. They do not need supplemental feeding if they are in a good water flow area that whisks by food you have put in for the fish, enabling the polyp to capture its meal.