[I dont know what this is]

So my friends brothers tank started accumulating this and neither of us know what it is or how to get rid of it. I dont know if it's slime or biofilm or mold and unfortunately I dont have any water perameters since this isn't my tank or one I have acess to. Any help is appreciated in getting to the bottom of this mystery 

[Betta fins cut by filter]

My friends betta applesauce got into the filter last night and I have some anti bacterial medicine on hand but is there anything else we can do to treat her?

[New red dwarf lily bulbs growing mold?]

Sweet thanks for the help I had never seen biofilm before I just knew it existed I appreciate the help a lot

[New red dwarf lily bulbs growing mold?]

I bought these bulbs recently and followed the instructions on their description when I got them Saturday January 16 and it hasn't been that long before they started growing this white stuff on it can someone please inform me if this is mold? And if it is should I see about getting new ones or will these ones be fine?

My tank parameters:

Fresh ph: 6.0

Nitrate: 40ppm

Nitrite: 0ppm

Kh: 0ppm

Gh: 30 ppm

Ammonia: 0