I've never had to cut my anubias. It's pretty slow growing. Java fern on the other hand will start growing roots and leaves off of the other leaves. I cut those off and plant them once they've gotten pretty big with enough leaves on them. Sometimes they'll just fall off by themselves, but it takes a while and I prefer just to cut them off. I attached a picture to explain what I'm talking about. When I first got java fern, I was worried it was dying because it had fuzzy brown strings growing off it it - but they're just roots.