That's probably a protein film; they're pretty common in tanks with little surface agitation. As far as I know they're harmless to turtles.

Saltwater aquarium enthusiasts use a device called a "protein skimmer" to deal with this problem, but I don't think they work in freshwater systems. An air bubbler, waterfall, or water spray can help, anything that disrupts the surface. You can also just use a fine mesh net to scoop up the gunk periodically and dispose of it.

[ Reply To This Message ] [ Subscribe to this Thread ] [ Hide Replies ]