Freshwater Aquarium. Feed the Fish in your iPhone

Freshwater Aquarium is a cute app that replicates an aquarium with fish on your iPhone. Like Koi Pond, its not likely that you will use Freshwater Aquarium a lot, but at $0.99 its cute enough to marginally justify the cost of entry. Other than watching fish (with the ability to scroll up and down in the aquarium), you can also feed the fish and exchange the fish (by "buying" and "selling" them), to create you own custom fish tank.