Scolopsis bilineata inhabits the sand-rubble fringe of coral reefs (Allen and Erdmann 2012). Greater abundance of species occur in areas of with benthic cover of coral, and lower abundance in areas with algal cover (Boaden et al. 2013). Scolopsis bilineata are nocturnal, micro-carnivores, using shelter sites adjacent to sandy areas where they migrate to feed (Boaden et al. 2013), primarily on small fishes and benthic invertebrates (Russell 2001). Scolopsis bilineata exist as solitary individuals or in small groups (Allen and Erdmann 2012); adult fish are most commonly found in pairs, with indications of probable reproductive basis for pair forming (Boaden and Kingsford 2013). This species changes sex from female to male but there is no evidence of functional protogyny, and sex change is pre-maturational and non-functional (Boaden and Kingsford 2013). It exhibits an asymptotic growth pattern, with majority of growth during the first 4 to 5 years (Boaden and Kingsford 2013). The maximum recorded length of S. bilineata is 23 cm TL (Longenecker et al. 2014). Juveniles are Batesian mimics of several species of blenny, genus Meiacanthus (Allen and Erdmann 2012).
Although this species appears occasionally in local fish markets and it is sometimes taken live for sale in the aquarium trade, there have not been any observed or inferred population reductions resulting from these events. There are no known major threats to this species.