The Hard Tube Coco Worm is also commonly known as the Hard tube feather duster, Protula tubworm, or Hard tubeworm. It exhibits a crown with varied colors that adds a splash of colors to your reef tank. The Hard Tube Coco Worm secretes a calcareous tube that is approximately « inch in diameter and 5-8 inches long, to keep its vulnerable worm body. So, keeping the Hard Tube Coco Worm in a large setup is advisable. When frightened, it quickly retracts its crown and closes its operculum to shut the top of its tube. The Hard Tube Coco Worm usually anchors its tube in a crevice of rocky reef or in the gravel along current-swept reef slopes. The aquarium should be well established with rock work, along with sand gravel and sand substrate. Also, the Hard Tube Coco Worm needs appropriate amounts of calcium, and proper alkalinity to grow, and is extremely intolerant of poor water quality and copper based medications. It is difficult to maintain in captivity, and will need supplements of phytoplankton and liquid organic foods for its continued good health. The Hard Tube Coco Worm is a peaceful species and is compatible with coral reefs. Therefore, it is absolutely safe to keep it in a reef tank. It thrives well in a temperature range of 72-78 degrees Fahrenheit, and pH of 8.10-8.40. At the time of feeding, the Hard Tube Coco Worm generally extends its fan to capture prey, and its radioles or feathers helps filter the food from the water current. It can be fed with phytoplankton and zooplanktons. The Hard Tube Coco Worm is non-poisonous and non-aggressive. If it is unable to adjust with the water parameters, it may shed its tube and may die eventually. Therefore it is very important to be vigilant towards any slight change in the water; that may affect its growth.