aka. SFS. A common problem caused by insufficent HUFAs in the diet during larval development. Symptomatic fish will freeze or faint and drift to the bottom. SFS is brought on by sudden stimuli, including turning on the lights, additions of food, and sudden disturbances (including netting). What actually happens is the stimuli essentially short-circuits (shocks) the nervous system and the fish becomes paralyzed. Depending on the severity and frequency of the event(s), it is often lethal. SFS is readily prevented and corrected, through enrichment of live foods using phytoplanktons (alive or pastes) or if your using dead or prepared foods, then the use of a liquid HUFA suppliment such as Selco, Selcon, Zoecon, etc.