The hidden treasure theory is formed on the basis of several architect models kept in the glass aquarium at Tommy's Ocean View Apartment. The models include the Ocean Beach Lighthouse, a treasure chest, and the Chartered Libertine Lines shipwreck propeller. It is a feasible code left by the developer, that a treasure chest lies in the middle of the Ocean Beach Lighthouse and the shipwreck propeller. Several investigations demonstrated that the propeller is indeed a fragment of the Chartered Libertine Lines wreck. Although the treasure remains concealed in the wreck. Players have theorized that the treasure chest could be an indication to the Ocean View Hotel since they're both in the middle of the lighthouse and the propeller.
One of the oldest theories about the aquarium is that the terrarium in Tommy's Ocean View apartment contains basic versions of a rock arch and a lighthouse which symbolize the ones behind the NW Portland mansion of Mafia leader Salvatore Leone (Frank Vincent) in "GTA III." The open chest in it seems to refer to the open chest that Claude, the lead character of "GTA III," finds at Donald Love's place as he realizes that Donald Love has disappeared. A poster of Claude is on the Ocean View wall.
During an internal file search, players viewed the model of the shipwreck and concluded that it was entirely hollow and no such treasure was concealed in the wreck, but the myth still remains possible.