Fish Bowl Gelatin:
Fills a 2 1/2-quart fish or glass bowl
1 two-liter bottle lemon-lime soda, flat
4 1/4-ounce packages unflavored gelatin
2 drops blue food coloring
2 ounces gummy fish
Place 1 cup soda in a large bowl. Sprinkle gelatin evenly over soda, and let stand to soften, about 5 minutes.
Place 2 cups soda in a small saucepan over medium heat. Heat until just before a boil. Add the softened gelatin, stirring to dissolve the gelatin completely over the heat, about 2 minutes. Remove from heat. Add the remaining soda and food coloring, and stir to combine. Pour the liquid into the fish bowl. Using a damp paper towel, carefully remove any bubbles that have formed on the surface. Transfer to the refrigerator to chill overnight.
When ready to serve, use a sharp knife to make vertical slits in the gelatin; insert the fish in a random pattern to make it look as though they are swimming in the bowl. Keep refrigerated until serving. Serve within 6 hours.
Note: To make the soda go flat, twist off cap, and let the bottle stand at room temperature overnight.