I just got my first system built and up and running over the last several weeks.  I've got a 10-gallon white rubbermaid "garbage" can on the floor for my goldfish.  A mini-jet 404 pumps water up into 4 bus tubs (bought these and the can from a restaurant supply store) that are connected by 1/2 inch pvc pipe.  I have an adjustable stand-pipe in the fourth one that drains back into the fish barrel.…