Each pet can aid the player during gameplay. While 28 pets can be earned throughout Adventure mode, each level requires the player to pick three pets. During an initial playthrough of Adventure mode, at the end of each level of a tank, the player receives a new pet from the egg. In each level, the player must earn enough money to buy three egg pieces to advance to the next level. In Adventure mode, a player advances through four tanks, each with five levels. Insaniquarium can be played in five modes: Adventure, Time Trial, Challenge, or Virtual Tank.

The aliens must be clicked on repeatedly with the mouse pointer in order to defeat them. In addition to feeding the fish, the player must protect them from aliens that periodically enter the tank and attempt to eat them. For example, guppies eat fish food bought by the player, and carnivores eat little guppies. The method of feeding depends on the type of fish to be fed. Each creature must be kept alive by feeding. The coins will disappear if they reach the bottom of the tank. Guppies and other fish drop coins, which can be collected by the player and used to purchase fish food and upgrades, such as more aquatic creatures, food that can keep the fish full for a longer period of time, and laser upgrades to repel attackers. In the game, the player must manage a tank of guppies and other aquatic creatures, and each stage begins with two guppies in the tank. Insaniquarium is a virtual pets simulator with a blend of elements from action, strategy, and puzzle video games. Screenshot of gameplay from Insaniquarium

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