Back to the Cryptocentrus gallery

Click the image for a final, full res version

Common Name/s: Yellow / Sulphur Watchman / Prawn Goby
Maximum Adult Size: 10cm
Natural Distribution: Western Pacific: Yaeyama Islands, Japan to Singapore and the southern Great Barrier Reef; Palau and Truk in Micronesia
Depth Range: usually 10 – 25m
Species Notes & Captive Care Notes: A resident of the tropical West Pacific, the Sulphur Watchman Goby favours a water depth range of around 10 – 25 metres (although it has been observed in shallower water). Its chosen habitat is usually a protected sandy lagoon or slope with clear water. Here, the goby inhabits a burrow that is constructed by its commensal Alpheid shrimp partner. In this mutually beneficial arrangement, the goby keeps watch for predators (hence the ‘watchman’ name). The shrimp reciprocates by maintaining the burrow while using its long antennae to keep in contact with the goby at all times. The movements of the goby therefore keep the shrimp alert to danger. This species is generally hardy in captivity and, especially if kept with an Alpheid shrimp partner (such as Alpheus bellulus), provides a fascinating subject for even a small tank of around 15 UK gallons. As a bottom dwelling species, it may sift through a fine sand substrate for food but it usually adapts to frozen meaty foods and even pellets quickly (much more so than some of the other ‘Sand Sifting Gobies’, many of which are far less hardy). Although generally peaceful, take note that this species may fight with other bottom dwelling species particularly if kept in too confined a space. It should not be kept with large aggressive species as this may cause direct injury to the fish or keep it in hiding so much that it starves to death. Certain authorities suggest that two colour forms of this species exist, and this can occasionally be seen in specimens offered commercially. One form is a bright yellow, while the other is a pale grey. Both of these forms have iridescent blue flecks and spots on the head and darker bands on the flanks may be evident (these may be stress related). Overall, coloration and patterning is variable and some suggest that it may even be sex related. Take note that there are a number of other species that look very similar, C. ??? and for example. Spawning this species in captivity is said to be fairly easy and the best way to achieve this is said to be to add a large grey specimen along with a smaller yellow specimen. The only problem is that the fry are very small and require small strain rotifers (such as Brachonius rotundaformis) as a first food. As a final note, take into consideration that this species may grow to around 10cm in captivity and live for several years.

References / Further Reading:
IUCN page with zoomable range map