This is probably a very silly question. But our filter makes quite a loud "whirring" noise. Does this bother the goldfish? My DH says it must drive them mad! Do all filters make this type of noise? Thanks.
Not sure if it bothers them or not, is it very loud? It shouldn't be whirring really, it might help if you give them impeller a good clean. Has it got a venturi on the outflow? It's a little gizmo that makes the filter shoot out loads of bubbles in the outflow of water. They are bloody noisy and not necessary so if there's a way to ditch it then you can.