When I put some shrimp in my Betta's tank I noticed some duckweed was in the bag they came in. I decided to pick them out and put them in his tank. They are starting to multiply. But noticed this morning that there was this mungy white stuff below their roots. In the picture the mung is attached to the fake betta log with the duckweed above it. Normal I guess or something need to worry about? Have never done live plants in an aquarium.