Hi,
Just checked my wine, made from grapes from my garden. It is currently aging, checked them last night and saw 2 had something on the top of the wine.
Floating suggests an aerobic organism as Acetobacter. (we all have had this). Wipe clean with Q tip or paper towel on a stick. Treat with 50 ppm of meta and try to layer 100 ml of grain alcohol on the surface. Next check air lock and is the cork getting bath/ not seating.