The nitrogen cycle will not begin until you add the fish, so running an empty tank for several days will not help. Since your fish tank is brand new, you might want to consider making partial water changes of about 25 per cent of the total water volume every few days for the first week or so. You can find Goldfish food at almost any pet shop. Overfeeding is a common problem in an aquarium. It is important not to overfeed, because excess food will become debris adding to the ammonia levels. This is especially important in new aquariums that lack nitrifying bacteria. Test the water P.H. every day within the first month. Watch the tank for cloudiness; if the aquarium becomes cloudy, it may be necessary to add a clarifier. The last category of saltwater aquariums is the specialty aquarium. An example of a specialty aquarium would be an aquarium full of sea horses. Sea horses should not be kept with any other type of fish or marine life, because they are timid and slow eaters. Their food source could easily be taken away by other tank mates. Should you already have one, be sure to keep an eye on the temperature of the tank and you may also want to limit the time in which a light is used. Any increased heat source will speed up the production of algae inside the aquarium. If your tank is located in direct sunlight and you are having an algae problem, it is best to relocate the tank. They will grow vertically and sprout shoots at the joints of the leaves. When these shoots grow to be a couple of inches, it is time to cut them and plant them individually. Live plants may be kept in aquariums alone or with fish. The plants may even be used as a food source for some species of omnivorous fish. Since there are currently no fish in the tank this will take some time. It usually takes about four to six weeks. Once you have purchased your fish, let them float on the surface of the tank in the bag for about fifteen minutes. The purpose of this is to allow the fish to become acclimated to the water temperature in the aquarium.