Stigmatogobius is a genus of small gobies in family Gobiidae, distributed widely across South and Southeast Asia - Indonesia, Malaysia, Thailand, Singapore, Myanmar, the Philippines, Bangladesh, and India. The atlas covers 2 species at a compact 2.5–3 in. Like many gobies of this region, they are typically found in brackish, tidally influenced water - river mouths, mangrove creeks, and coastal lowland streams - rather than fully freshwater habitats, and share the goby body plan of a blunt head and fused pelvic fins forming a sucker-like disc.
The knight goby (Stigmatogobius sadanundio) is the genus's aquarium-trade representative and a long-standing brackish-tank fish, recognizable by its silvery body scattered with bold black spots; it is a semi-aggressive, territorial feeder best kept with water that carries some salinity rather than as a pure freshwater community fish. S. pleurostigma has little presence in the hobby by comparison. The IUCN picture is incomplete rather than concerning - one species is Least Concern and the other Not Evaluated, typical for a widespread brackish-water goby genus with uneven survey coverage across its range.