Ice cubes REAL Gummi brand gummy fish Dissolve gelatin completely in boiling water. Combine cold water and ice cubes to make 1.25 cups ice and water.Add to gelatin, stirring until slightly thickened. Remove any unmelted ice. If mixture is still thin, refrigerate until slightly thickened. Pour thickened gelatin into 4 dessert dishes (or clear cups or glasses). Suspend gummy fish in gelatin. Refrigerate until set, about 1 hour.