what causes this to happen?

[BfishLpond78]

What cause a new leaf to grow off an older leaf? What is thw brown stuff hanging down?

 

[jetajockey]

That's the way that java ferns propagate, they grow new plantlets on the ends of their leaves, eventually it will disconnect and float around till it anchors on to something.

 

[BfishLpond78]

Thank you!

Do you have any experience with narrow leaf hydro? Mine are doing pretty bad...

Also you will notice my sword is lacking something too...any ideas?