I'd hold off and get a 125g tank. A 20g is very difficult to maintain when it contains goldfish. I quarantined mine in my 10-20g tanks for a month and the maintenance was rather tedious often involving twice a day water change as they stir the poop and eat like pigs around.Muske;3248426; said:Is a 20 gal. OK for a 18-24 month growout? Don't have the room for a larger tank at this time. Or, should i hold off and do a 90-125 when I get my basement