What's the green slime in the Schuylkill River?

PHILADELPHIA (WTXF) - You may be wondering what is causing that green slime in the Schuylkill River. Turns out, it may not be as bad as it looks.

FOX 29's Karen Hepp spoke to some experts who explained what that green stuff is exactly and if we should be worried.

The thousands who run, bike, row even drive by every day are scratching their heads. Experts say it is normal but it isn't algae. From SkyFOX our producers thought it looked like green slime.

"The green splotches, getting lots of questions about the green splotches. There's nothing to worry about. The green splotches are actually a naturally occurring free-floating aquatic plants." said Kelly Anderson with the water department.

It is also known as duckweed, which ducks actually eat.

Anderson says it actually shows the river is healthy and is totally safe. But why did we get so much and all of a sudden? Monday's big rain washed it down that's why.