Seems to be biofilm. (think that's what it's called.)

My anacharis has it all the time, seems to be normal for floating plants. My hornwort also has that.

 

So it's just from the tank cycling? I recently added TSS to my tank to insta-cycle it (a week ago).

 

I don't think so. My tank has matured for over 6 months now, but my anacharis in my 3.5G don't seem to have any. Maybe it shows up like algae, when there's a small amount of nutrients?

 

It almost looks like they are shedding. But when I touched it and it came off on my finger, its almost like a slime.

 

whats your nitrate level?

My plants get this brown sloppy stuff on their leaves when there is not enough light and too much nutrients in the water. Try doing a water change.

 

I tested earlier today,

Ammonia 0
Nitrites 0
Nitrates 5