Aquarium is a card game that puts player interaction at the heart of the fun. Each game starts with an empty market and a shuffled deck of action cards, including ‘Feeding time!’ cards sprinkled throughout. On a player’s turn, the active player flips a card from the deck, looks at the market, and decides whether to buy or pass. If they pass, they receive two coins from the bank and a new card enters the market; if they decide to buy, the other players step in, each using one of their action cards in two distinct phases. In phase 1 they can add, remove, or swap market cards, or even swap fish in the active player’s aquarium. In phase 2 each player adjusts the cost of the market cards, raising, lowering, doubling, or halving the price, with the payment going directly to the card holder. Once the final cost is set, the active player can buy all the fish and plants on offer or none at all. Purchased fish go into the player’s personal aquarium; if there are two identical fish, the player can put them in a breeding tank that yields coins each round. ‘Feeding time!’ cards are revealed at random times, requiring players to pay a cost based on the stars on the fish and plants in their aquariums, while plants reduce the cost. Fish that aren’t fed disappear. At game’s end, players count the stars on their non‑breeding fish and receive bonuses for color and size collections. The winner is the one with the most stars. Aquarium blends strategic buying, card manipulation, and a captivating aquatic theme, delivering a tense yet humorous experience every turn.