$571.50. The list of items and their corresponding costs are accurate estimates for what it recently cost me to set up a 29-gallon tank. I could have spent much more on fish and equipment, but not much less. poorly maintained aquarium is an eyesore and the cause of death for the unlucky fish inhabitants. The cost of running an aquarium is important because if an aquarium owner is not willing to invest the necessary money and time in doing it right, then the fish will suffer and die as a result.