Tough decision. I was stuck on either new world or marine. I have a 275 gallon so far with 1 oscar and am planning to get more NW chiclids. However, since i am spending SO much time reasearching marine and understanding how to set up my own marine tank, i have found marine very intresting. The fish are amazing and have a lot of personality. There are SO many choices and each of them requires great care. Not many people have marine, and the time and money to take care of a marine tank. But if you do then i think a mrine tank is the most rewarding. If you compare 2 tanks, 1 being marine with live rock and corals, and comppare it to any FW tank ... the marine would look more gorgeous and its fact