The Blue Fin Watchman goby (Cryptocentrus fasciatus), sometimes referred to as the Y-bar shrimp goby, is similar to the Yellow Watchman (Cryptocentrus cinctus) goby that we produce. The Blue Fin watchman differs from the Yellow Watchman in that their anal fins, and sometimes their unpaired fins, are ornamented with iridescent blue stripes and dots and their body has patterns of white, black, grey and/or brown. Blue Fin Watchmans also grow slightly larger than Yellow Watchmans. Interestingly, Blue Fin Watchmans occasionally exhibit a yellowish body color, similar to their cousin species. The patterns of black and brown on their bodies can also vary considerably depending on their age, mood and environment. These prawn gobies are very hardy and make great additions to a wide variety of community aquariums. Although they’re “Cryptocentrus” these fish are not typically cryptic once they become comfortable with their surroundings.