Make the jello according the package directions pour powder into a bowl, add 2 cups boiling water, stir about 2 minutes until completely dissolved, add the cold water.
Pour approx. 1/2 cup of the jello into individual clear plastic cups and refrigerate for about 2 hours until it's soft set. You want it to be gelled enough that the fish won't sink to the bottom, but not so hard that you can't push them in.
Add the gummy fish and sharks (I found it worked well to spear a fish with a toothpick, push it into the jello, then use another toothpick to release it).
Put back in the fridge for about another two hours to fully set.
Now add the vanilla cookie crumbs (the sand). Next add the umbrellas