Static acute 96 hour tests were conducted with Mysidopsis bahia using either carbophenothion, cypermethrin, malathion, or 4-(tert-Octyl)phenol. The mysids were 24 hours old or less at test initiation. For each chemical, two replicate tests were conducted simultaneously with each of three rations of food provided. The rations chosen were 10 Artemia per mysid per day (A/m/d), and 110 A/m/d, clearly in excess of that necessary for good survival and growth. These rations were chosen after growth studies with Mysidopsis bahia using two types of Artemia salina indicated that only rations of 5, 10 or 30 A/m/d/ were different from 50, 70, 90 and 110 A/m/d as measured by dry weight.