I have both and I do find that the tropical fish are easier to care for. My goldfish are mucky pups! The only tropical fish I have had a problem with are the guppies, I just don't seem to be able to keep those for some reason. For the last 7 years I have had tetras (neons, black widows), corydoras, plecos, silver sharks, hatchet fish, angels). I would love a marine tank one day too.