Little Depot the goldfish is outgrowing her tank and I'm getting a bigger tank in a week or so. Does anybody have any suggestions on a good filter that is small and simple? I'm in a dorm room so I don't want a big elaborate setup, and I'll probably change the water often anyway but I want a filter in the new tank. I have no knowledge of what types of filters are out there as I've never had one in with my fish but I know I don't want charcoal and cotton like my mom's tank has. Is there any other kind even?