Write an article based on this "Pick rocks to create a theme. Use driftwood for a more natural touch. Use shells to create a miniature ocean. Use live plants to add a spark of green."

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Rocks can add a decorative touch to your aquarium. Choose from rocks such as lava rock, quartz, petrified wood, and slate. You can also use red desert rock, honey onyx, zebra rock, ice rock, or rainbow rock. Dark rocks like lava rock or slate create a more serious tone, while brighter rocks, such as pink quartz, will make it more cheerful. Large rocks that many layers and crevices help give your tank dimension. You can also pick rocks that have natural tunnels in them for your fish to swim through.  You can purchase aquarium rocks at pet stores. However, you can also pick up your own from local areas, as long as you follow a few safety tips first. Check the rocks for sharp edges. You don't want something that could cut your fish.  Make sure to test to see if your rocks are too basic (as opposed to acidic). You can test them one of two ways: 1) Drop a few drops of vinegar on it to see if it foams, or 2) Soak the rocks in water for a few days. Once you've soaked them, test the water to see if it's at the right pH level for your fish. Also, clean up your rocks. Wash them off, and then be sure to boil any rocks you find for a good 10 minutes to make sure you're not introducing bacteria to your fish. Driftwood is reminiscent of the beach, in particular, and it can give your tank an ocean-like natural feel. You can find driftwood along rivers and beaches. You might also catch some while fishing at a lake, as well as purchase it a pet store.  Check to make sure there's nothing living in the driftwood before picking it up. Wash and boil anything you pick up outside before putting it in your fish tank. Shells can also add a natural, beach-like feel to your aquarium. Smaller shells make your fish seem bigger in comparison, while using large shells can help you create a theme, such as an underwater mermaid kingdom. For example, you could use large orange or reddish scallop shells to create a mermaid's "home," by opening up the shell and placing a novelty mermaid in the bottom shell. Seashells mostly come in whites, yellows, browns, reds, pinks, and oranges, so keep that in mind when building your color scheme. You can use some mother-of-pearl shells that come in more brilliant colors.  You can find shells along the beach. You can also find some shells along rivers and lakes, though it depends on what animal species are living near there. You'll find many stores also sell a variety of shells.  Check for animals in the shell before taking it home. Wash and boil the shells to remove bacteria, and don't use them in in freshwater systems. In freshwater systems, they can add too much calcium or change the pH of the water. Plants can be used to hide away things you'd rather not see, like the filtration system. Make sure you use a variety of plants, as different leaf shapes and plant sizes will add visual texture to your aquarium. Make sure you don't place all the plants at the front, as you'll block the view. Instead, try using them as part of the background in your tank.  Live plants can be used in any type of tank, as long as the plant can survive in that type of water. For instance, plants that can survive in freshwater won't make it in saltwater, but you can use coral and algae in saltwater.  One problem with live plants is that they will die in time, which may affect the water quality. However, they can add a fresh look to your aquarium. One benefit of live plants is they consume nitrogen, found in your fish's feces. In addition, they use carbon dioxide and put off oxygen, helping your fish breathe.  You can buy aquatic plants and coral at most pet stores.