Posted: Tue Jul 17, 2007 12:46 pm
Angle the output of the filter so that it agitates the surface slightly, which should help. If you're feeding him foods/pellets in the tank that have a high oil content, it will also contribute to a slightly oily film. If you're not doing so, you could feed him in a separate container of water.
"You become responsible, forever, for what you have tamed." -Antoine de Saint Exupery-