Encheliophis chardewalli was described from a single cleared and stained specimen. Twelve years later, additional specimens were found in the lagoon of Moorea (French Polynesia) in association with their host, the sea cucumber Actinopyga mauritiana. These fish were used to consolidate the species diagnosis, to validate species status and to record sound production. This species is remarkable because of its ability to penetrate inside the cloaca of sea cucumbers having anal teeth and the fact this species is largely unknown despite it lives in lagoons in 1m depth. Encheliophis chardewalli produced three sound types: long regular calls made of trains of numerous pulses, short irregular calls characterized by a constant lowering of its pulse period and short regular call (or knock) made of 3 to 6 pulses. Comparison with other sympatric Carapini supports a large and distinct repertoire. Morphological characteristics could be the result of reduced body size allowing to penetrate inside a new host, thus avoiding competition and conflict with other larger sympatric Carapini species. This study highlights three different types of calls in a cryptic species and provides morphological information related to its way of life. The fish paedomorphic form could be due to requirement related to host distinctive features.