Reef aquariums can be tricky to maintain and must be thoroughly researched before attempted. 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. When starting any new aquarium, you should get everything in place before buying the fish. If you are going to put gravel on the bottom, you may want to put only a thin layer. This will make it easier to keep clean, as Goldfish tend to be messy. Make sure that you rinse the gravel thoroughly before placing it in the bottom of the tank. Tips on Aquarium Care and Cleaning The proper care and cleaning of your aquarium is the most important, yet most overlooked aspect of owning an aquarium. By avoiding the care and maintenance of a fish tank, not only will it lose the visual appeal, but your fish will be unhealthy and unhappy. By following a daily, weekly and monthly care program, you will maintain a beautiful, clean and healthy aquarium. When this happens, carbon dioxide is lost and plants will suffer. Also make sure the filter creates a current that keeps nutrients moving throughout the tank. By having a good chemical balance in the aquarium and having an efficient filtering system, you will be sure to have healthy live plant growth. It may take a little while for the fish to adjust to the new water, but after having followed all these steps, you can be sure that your tank is clean and healthy. You won't have to completely clean your tank for another 2 months. Always remember to change the filters if they are dirty. As an added tip, if you remove 20% of the water every month and replace it with clean water, this will cut down on the complete cleaning of the tank in the future. Just like any living creature, a fish's body requires water in order to function properly. Water is absorbed through a fish's skin in the freshwater environment. Alternatively, a saltwater fish actually has to drink the salt water, because the body fluids are extracted through the skin by osmosis. The salt is then excreted in the form of highly concentrated urine.