I have a Watchman Goby and he has yet to burrow....Matter of fact, I haven't seen a WG ever burrow. There are other Gobies that will though....WG seem to perch themselves on a rock and stare at you... Mine watches my every move..They do get a mouthfull of sand every now and again and filter it through their gills....Funny to watch... I don't think it will bother your DSB at all...