1.1 ,This guide describes procedures for obtaining laboratory data concerning the adverse effects of a test material added to dilution water—,but not to food—,on certain species of freshwater and saltwater fishes during 28 to 120-day (depending on species) continuous exposure, beginning before hatch and ending after hatch, using the flow-through technique. This guide will probably be useful for conducting early life-stage toxicity tests with some other species of fish, although modifications might be necessary.