This study examined the possible use of white LED strobe light as suppression of seaweed overbrowsing for the mottled spinefoot Siganus fuscescens. Effectiveness in avoidance response of S. fuscescens to strobe light flashing was compared in relation to feeding behavior of algal baits placed in front of a waterproof strobe light emitting device in two treatments of an open feeding space and two adjacent small feeding spaces with poor visibility in an indoor tank. Strobe frequency and irradiance of the light emitting device were 5 Hz and 43 Wm^{-2}(17,500 lux). Tests were videotaped, and behavioral aspects of feeding such as numbers of bites, numbers of visits to compartments with algal baits, and durations of visits were measured. In the open feeding space treatment, the fish showed little aversive responses to presence of the strobe light. In the small feeding space treatment, the fish showed remarkable avoidance to feeding within a compartment with strobe light flashed, while it showed no avoidance within another one with no light. Effectiveness of the strobe light associated with feeding space was discussed in reference to potential predation risk.