I have two ropefish, male and female (I believe) They are both about 6ish inches, Scyla and Decala. They enjoy infiltrating my internal filter system as well as cuddling...They are ALWAYS together.
My kkuhlis can't even uproot baby dwarf sag runners, all they do to disturb the sand is to stick their snout into the sand and shoot it through their gills.
Here is a picture of two of my plants, they were not in the tank a week, and they look like that. The one on the Left is the Japanese Rush, the right is the Ferny like plant...see? They just tear it off at the stem and leave just stubble for my plants. How can I make them stop!? That's 2.5 plants in one week!
The fern was a terresrial plant. It would have rotted in a few weeks and shot your Nitrates sky high. Think of the fish as doing you a favor, albeit an expensive one.
I have a pleco that was tearing up my plants. I put lettuce in there for the snail, the pleco loves it. The Pleco tears up the lettuce and leaves the plants alone.
Not sure if putting lettuce in the tank would help. i'm sure there are others here that know a lot more about this than I do.