I am very new to Saltwater lifestyle and I have a 20 gallon standard tank. I have been doing a lot of reading and research about what it takes to make a good tank. I know a good supply of Live Rock and Live sand is a must to any tank big or small. I am needing to know about the Skimmer and the power heads I would need. My overall goal is to have a pair of Mandarin Dragonet. I am planning to have another tank just for raising Cope's for them. Let me know if you guys have any suggestions. Thanks.