The purpose of this study was to Composition Brachyura cryptic organism (class crustacea) from genus Pocillopora that found on dead corals and to find out the environmental conditions of Sabang waters. The method used in this research was exploring method using Purposive Sampling. The data were collected in August 2016 in three observation stations: Seulako Island, Rubiah Island, and Sumur Tiga. All stations were categorized as deep waters (7-10 m) which have different types and substrate characters. The water quality parameters measured in this study were temperature (300C), salinity (29.5‰ - 32‰), and pH (7). The results of the study showed that there were five families found (Xanthidae, Portunidae, Majoidea, Pilumnidae dan Trapeziidae) with total of 142 individuals that spread into three stations. The most common individual was found in P. Seulako with dead coral volume of 3.2 liters, while the least was found at the site of Sumur Tiga with a dead coral volume of 1.2 liters. The range of dead coral volume found at the P.Seulako, P. Rubiah and Sumur Tiga was 1.2 - 3.2 liters.
