Fish as pets Are you an aquarium person? Having an aquarium can be fun and relaxing. Starting out you don't have to go big right from the start. Starting small is the best way if you're new to keeping fish. Start with a ten-gallon tank they are less expensive and readily available at many larger department store. However, I suggest supporting one of your local pet store or aquarium stores. Starting with a ten-gallon tank has two very good reasons. You can learn what it takes to establish a good fish environment. With less expense in equipment and livestock. As you grow in the comforts of keeping an aquarium and decide to graduate to a larger environment with the more delicate tropical fish you will have a good isolation tank for the times you need to treat a condition that a fish may have or you find that you have an aggressive bully in the tank and can isolate it for a while.