Ice cubes REAL Gummi brand gummy fish Dissolve gelatin completely in boiling water. Combine cold water and ice cubes to make 1 1/4 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.