Not too long ago we picked up a small packet at the store for $5. We brought it home and emptied the smallest item into a tank of spring water, and waited to see what would happen. It took a few days, but we ended up with two Triops inhabiting the tank.
The Triops (both named "Fishy") are somewhat like incredibly small horseshoe crabs, swimming speedily around the small tank. They feed off a slice of carrot and a pellet or two of fish food each day.
So far Norah has not decided to investigate.
