The Pets Game and Gamebrew websites offer good fish aquarium games for players to enjoy online. These games are available to play for free and registration isn't required.
As of July 2015, the Pet Games website offers four aquarium games for players to enjoy. The player chooses a game to play from the provided picture, description and star rating. After choosing a game, the player begins by clicking Play Now or the title of the game.
Gamebrew provides players the chance to play "Insane Aquarium." In this aquarium game, the players get the chance to grow their fish by eating smaller fish. However, there are larger fish and other dangers lurking in the aquarium. The oyster contains a pearl that boosts life but the fish gets trapped if it is in the oyster when it closes.