[B][SIZE=4]For a goldfish tank, what have you found to be the best filtration system? By "best," I mean most efficient at converting ammonia, but [U][I]also[/I][/U] easy to maintain.[/SIZE][/B]\n\n[LIST]\n[*]An HOB [hang-on-back] filter\n[*]A canister filter\n[/LIST]\n______________________________________\n\nPlease elaborate on brands, pros & cons -\- basically, anything that will help me make a decision.\n\nI will be housing [I][B]one goldfish that's about 4" long[/B][/I] [body length] on a permanent basis. He is a "special needs" goldfish that needs to be out of the pond. Going to start out using my 20 gal tank, but will go bigger if necessary.\n\nThanks for your help!