Once the aquarium is ready, start with anemones and clown fish. They are the hardiest of reef species, and who wouldn't love to have Nemo swimming around in their living room? Monitor the marine life closely. Check the activity levels of the fish, and watch for stress. Stress is the most common cause of sickness in fish. Aquarium Care for Sand Sharks Sand sharks are viewed as the most timid and least aggressive of the shark species. Sand sharks are usually smaller in size than other sharks and move fairly slowly. These sharks are found all over the Atlantic Ocean, and are the most common type of shark. Although these sharks would seem to be the perfect aquarium kept fish, because of their smaller size, they are not. Aquariums need little care in comparison to cats, dogs and even birds. When going out of town, it is acceptable to leave the fish alone for a week or even longer. Just have a neighbor feed them once or twice. There is no grooming or bathing needed for fish. While a home aquarium does require regular maintenance and cleaning, it is minor compared to the care required for larger pets. Be aware of this as you position the coral in your tank and try to keep coral pieces at least 6 inches away from others. As your consider the placement. Also take into consideration the available lighting where they are placed. If you have additional light sources aside from the tube in the hood, bubble coral should do well anywhere in the tank. Place these corals into the live rock as you did with the previous set of coral. Now you have succeeded in creating your reef aquarium. During the course of the 10 to 12 week mark, you may begin adding your fish to your underwater world. It may seem a long drawn out process to get a coral aquarium up and running, but the time and hard work will pay off for years to come. One reason that freshwater fish are hardier than saltwater fish is the saltwater itself. 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.