The stability of oversaturated solutions of the highly lipophilic molecule deltamethrin under the conditions of continuous agitation and oxygenation by air bubble flow in a toxicologic test on fish embryos was studied. In polyethylene, glass, and Teflon containers, the 24-hr adsorption rate of 1 mg/l solutions was over 80%. Improvement by Sharon and Solomon's PEG-glass pretreatment did not exceed a small percentage. After agarose precoating, the adsorption rate in the glass or polyethylene containers was reduced to about 20%. The stabilizing effect of precoating agarose containers diminished with the concentration of the solution.