Caulerpa control advice?

[Fish]

Hi all,
I have two pieces of rock in my 20H that have caulerpa growing on them. I have tried to remove it by hand but the rock is so pourus that it is impossible to get all of it. Plus, pruning is intrusive and messy for the tank (plant bits always end up floating around). Can anyone suggest a fish or invertibrate that would help me clear this caulerpa out?

Would a lawnmower blenny help? I don't know, its name makes it sound like its fit for the job .

As always, thanks for the help.

- Chad