Step 1: Prepare the Jell-O. In a large bowl, whisk together the blue raspberry Jell-O powder and boiling water until completely dissolved. If using unflavored gelatin, dissolve it in a small amount of the boiling water first before adding to the main Jell-O mixture.
Step 2: Add the cold water and stir well. Allow the mixture to cool slightly at room temperature, about 10-15 minutes, before pouring into the clear plastic cups. This prevents the cups from warping and allows the Jell-O to set more evenly.
Step 3: Fill each of the 6 clear plastic cups about two-thirds full with the cooled Jell-O mixture. Carefully place the cups in the refrigerator and chill for at least 3-4 hours, or until the Jell-O is fully set.
Step 4: Once the Jell-O is firm, it's time to decorate! Sprinkle about 1 tablespoon of crushed graham crackers into each cup to create the 'sand' at the bottom of your aquarium. Gently push 1-2 gummy fish candies into the Jell-O so they appear to be swimming.
Step 5: Add mini green sour belts or apple licorice strings as 'seaweed,' placing them upright in the Jell-O. Scatter rock candy, Nerds, or small candies around the 'sand' for 'pebbles' and extra color. If desired, top with a dollop of whipped topping or whipped cream for 'waves' just before serving.
Step 6: Serve immediately and watch the delight unfold! Enjoy your charming Edible Aquarium Jell-O Cups.