Family Carapidae is a unique family of fishes known for their peculiar habits of living inside sea cucumbers. These fishes are also called pearlfishes or sea cucumbers fishes because of their peculiar behavior. In addition to that, they are sometimes referred to as parasitic fishes, as they use their host as a shield against predators. Pearlfishes belong to the order Ophidiiformes and are found in the oceans around the world. Other synonyms for Family Carapidae include sea cucumber dwelling fishes, commensal fishes, holothurian fishes, and endoparasitic fishes. Despite their unusual lifestyle, pearlfishes serve as an important source of food for larger fishes.