Fish is an aquarium simulator. It allows you to add fish to an underwater environment and customize them. Fish show complex behavior. You can feed them, see their evolution as they grow, use different cameras to track them, and save different aquariums for later use. Fish can also be shared with others over the local network using Rendezvous.

Don't worry about your fish; they are saved when you leave the application... The save function is only intended to be able to save multiple aquariums.