Java Fern

[Biulu]

I have noticed that larger leaves from java ferns are very prone to getting black spots. I just received a large java fern from a friend and again, the plant grows well, but as soon as the leaves get somewhat older, they start getting the black spots. According to him this is normal for this plant, but I have been seeing enough tanks with green leaves of java fern to know that it is not true.

What is causing these black spots and how can it be avoided?

 

[SO19Firearms]

What is causing these black spots and how can it be avoided?

Reproductive sites? Not sure you can avoid it, just pull off the plantlets when they have a rhizome and re-attach them.

 

[Biulu]

No, it are not reproductive sites as they are in the middle of the leaves. It is really a necrosis, a spot where the tissue dies off.