Nano Aquarium is a virtual aquarium app that aims to provide a calming and relaxing experience to its users. It features a natural-looking aquarium, resembling the Iwagumi style, with a shoal of fish swimming in it.

The free version of the app offers a single type of fish and up to 8 fish in the aquarium. It also comes with one aquarium style and allows users to tap on the screen to feed the fish. Upgrading to the paid version offers 7 types of fish, up to 50 fish in the tank, and 5 aquarium design options. The paid version also removes the top ads image in settings and still allows users to tap on the screen to feed the fish.

The latest upgrade, Upgrade 2, offers 8 additional aquarium styles, including Old Tree, Small Roots, Big Old Root, Root with Moss, White Root, and 3 new Rock styles. The app also features fishes that avoid obstacles.

Overall, Nano Aquarium is a simple and straightforward app that provides a peaceful and serene experience to its users. It is best used for phones and is a great way to relax and unwind after a long day.