Brackish water is more difficult to maintain because it is a mixture of both salt and freshwater. In the wild these fish live in areas where ocean waters meet streams or rivers. The Albemarle Sound is an example of brackish water. The same general type of equipment is required for brackish water and saltwater aquariums as fresh water. Check with your retailer on the specifics for adding live plants. Some live plants need to be anchored, while others can be left free floating. Next connect the air pump and filtration system, and fill the tank the rest of the way. Lastly put the lid on the tank and let it cycle for one to two days before adding any fish to the tank. Ideal temperature for a marine aquarium is between 75 and 79 degrees Fahrenheit. It is also important to test the P.H. of the tank. Ideal P.H. is somewhere between 8.3 and 8.4. Test kits can be purchased online or at your local pet store. They same store will also carry any solutions necessary to adjust the P. Now it is time to purchase the fish! Buy hardy fish such as danios, barb, gouramis, and live bearers. They should be able to withstand the high nitrite levels and ammonia in the new aquarium. Only introduce about four fish at a time. Float the fish in the bag in the aquarium for about fifteen minutes before adding them to the tank. Filters collect waste excreted by the fish and left in the tank in the form of excessive fool. The filters will eventually fill with debris and be unable to do their job unless they are cleaned. In addition to eliminating waste, filter sometimes act as an aeration device cycling oxygen through the tank. It is possible to mix guppies with other varieties of fish. However be careful when mixing because, guppies are targeted as easy prey due to those fancy tails. Guppies breed very quickly, usually about every three to four weeks. They will interbreed amongst themselves, so the aquarium could very quickly become filled with many different varieties of color.