Some of the most common are Button Polyp, Yellow Polyp, Hairy Mushroom Coral and Bullseye Mushroom Coral. Make sure when adding your coral, it is attached to the live rock at the bottom of the tank. Wait another 2 weeks. Don't get frustrated... you're almost there! During the eighth week, you can add Aquacultured Coral such as Pumping Xenia, Starburst Polyps and Spaghetti Finger Leather Coral to name a few. Most common are goldfish and guppies, but there are a multitude available and you will be able to have an array of fish living in your coldwater tank. The supplies you will need to set up your aquarium may seem lengthy, but it is actually a much shorter and cheaper list than that of a heated freshwater tank or a saltwater tank. All you need to do is go to the pet store and pick out a tank and the prettiest fish in the store, and you are ready to go right? Wrong! Starting up an aquarium is a process. It takes time and a lot of patience. If you are a beginner, it is recommended that you start out with some hardy freshwater fish, but don't buy the fish just yet. Although these sharks would seem to be the perfect aquarium kept fish, because of their smaller size, they are not. They still grow to reach an average length of about five feet, and can weigh as much as three hundred pounds. This is really too large to keep in a home aquarium. The population of these sharks has dwindled in recent years, due to fishing activities. Change approximately one third of the water in the aquarium every one to two weeks. Water from the tap should be treated accordingly before adding to the tank and adjusted within two degrees of the aquarium. Again, check with your local retailer when purchasing fish. Some treatments allow the tap water to be ready in as little as an hour, while others need to sit overnight before being added to the tank. They require a water temperature between fifty four and fifty nine degrees Fahrenheit, a P.H. between 8-8.4 and a salinity content of 1.024-1.025. Luckily they do eat the same food. They feed off of a diet of small pieces of raw fish, shrimp, squid and mussels. When keeping cold water invertebrates such as the species mention above, it is a good idea to keep a separate tank full of shrimp, mussels, and scallops to be used as a food source, if you wish to use fresh rather than frozen foods.