Bring the soda, blue drink and sugar to a boil in a medium saucepan over medium-high heat. Remove from the heat and slowly whisk in the gelatin, whisking continuously until dissolved. Pour the gelatin mixture into a medium bowl and refrigerate until it just begins to thicken (it should be thick, but still liquid and pourable), about 1 hour.
Slice the pound cake into eight 1/4-inch-thick slices. Remove the push parts of eight 7 1/4-inch-tall pushable pop molds from the tubes. Push the circle side of each mold into the cake slices to make a circle that fits snugly in the mold. Return the push part to each tube. Spoon 1 tablespoon of the tiny crunchy candy into each mold.
To make the seaweed, fold each licorice piece in half and then twist the folded part so that the 2 ends are sticking up and resemble aquarium seaweed.
Reserve 1/2 cup of the gelatin mixture in a small microwave-safe bowl. Using the remaining mixture, fill each mold halfway (about 1 1/2 tablespoons). Press a piece of licorice seaweed into each mold. Press in 2 fish per mold. Fill each mold the rest of the way with the gelatin mixture (about 1 1/2 tablespoons), leaving about 1/4 inch at the top; tap to remove any air bubbles. Microwave the reserved gelatin mixture until liquid, about 30 seconds. Spoon 1 teaspoon into each mold and refrigerate until completely set, about 3 hours.
Copyright 2018 Television Food Network, G.P. All rights reserved.