Starting off, the player is given 200 shells to spend and can earn more through playing Adventure, Time Trial, and Challenge modes and caring for their fish which also drop shells. Virtual Tank fish can never die, but still require at least three daily feedings to keep their mood content; if their mood drops, they may not produce shells until made happy again. Fish in the Virtual Tank take much longer to mature and grow than in other game modes, roughly a week per growth stage with proper care.
Players have a set of buttons at the top of the tank to perform different actions.
Store - The store button takes players to The Fish Emporium where they can purchase an array of fish, upgrades, and backdrops for their tank. Meryl is the store clerk and gives brief comments about each item for sale.
Fish - The fish button brings up a display of all of the players currently own fish. Here, players can view information about each of their fish, including their interests, hometowns, date of purchase, and their mood. Players also have the option to sell their fish or hide them from the tank through this interface.
Pets - The pets button allows players to annex pets they've earned through Adventure Mode into their tank. By default, only three pets can be selected but up a maximum pet limit of 11 can be obtained.
Tank - The tank interface is an options menu specifically for Virtual Tank mode. It allows players to toggle fish names, Bubbulator visibility, Alien Attractor enabling, shell dropping from fish, and visibility of fish hunger. Additionally, a player can enable screensaver mode and switch between backdrops here.
Back - The back button returns the player to the main menu. This can also be achieved using the Menu button above the shell count.
Main Article: Virtual Tank Fish
The fish available in the virtual tank are mostly the same as other game modes (guppies, carnivores, starcatchers, etc.) but also includes a handful of exclusive fish, several fish attributes, and pre-named fish that have very special traits.
The Star Guppy of Tank 2 is the only fish found in the Adventure, Time Trial, or Challenge modes that cannot be obtained in the Virtual Tank.
Main Article: Virtual Tank Upgrades
There are various upgrades to improve a player's tanks. Most of these upgrades can be purchased from the emporium while others are purchased after playing levels in other game modes. Upgrades include:
- Bubbulator: Increases maximum fish population from 10 to 20 and costs 20,000 shells.
- Alien Attractor: Spawns aliens that don't harm store-bought fish and can be defeated for blue shells. It costs 50,000 shells.
- Food Upgrade: Upgrades regular fish food from flakes to vitamins and costs 20,000 shells.
- Backdrops: Different backdrops can be purchased for 15,000 shells each for the player's aesthetic pleasure. There are six different backdrops.
- Pet Limits: After purchasing all bonus pets, the maximum amount of pets allowed in the Virtual Tank can be increased as well, starting with four for 40,000 shells, then seven for 45,000 shells, and finally 11 pets through unlocking Sandbox Mode.
Players have the option to set their Virtual Tank as a screensaver. It will run with fish and pets the player has selected in the game without running the actual game. The shells collected while the screensaver is running will be added to the user account. Leaving the screensaver on for a long time can give you many shells.
There isn't any way to feed fish manually so the tank needs to set up in a manner that automatically feeds fish and collects money. For feeding fish, Prego, Zorf, and breeders will be able to feed carnivores and guppies. Zorf can be combined with Brinkley to feed starcatchers. After purchasing the Bubbulator, Alien Attractor, and Food Upgrade, players have the option to buy Cookie who will feed all types of fish besides regular fish food eaters.
More details can be found on the Pet Combinations page.