I noticed last time I performed a water change there seemed to be what looks like pieces of slime floating around the tank. I've posted some pictures below (sorry for the poor quality). It looks similar to the slime coat which comes off a betta after it passes away, but there's not anywhere near as much of it. The pieces tend to break apart when disturbed and form many smaller fragments across the top of the water.
Any ideas on what it could be? I don't think it's a problem, but I wanted to get a second opinion.