I had a blue & black ribbon eel for about 3 1/2 years in my tank. I ended up having to donate them when I had to tear down my tank a few years ago. At that time my tank was mature & running for almost 10 years. I never had problems with them eating anything in my system. I would feed them twice a week with tweezers. They are kinda hard to get to eat but once they do they ate great for me.
I would like to add, be very cautious of your rock work because they have to create a home in your aquarium & that usually consisted of burrowing under a rock, so make sure things are stable so they don't fall. They can get between 3&4 feet long so that's a good sized hole under a rock. Also they are great escape artists & love to swim through your overflows. One time when my black one was new, I couldn't find him for 3 days, thought he was a goner, ended up finding him in my sump. Another time he was "carpet surfing" as, Dave put it, (lol). My cat was actually playing with it like a piece of string, when I noticed, I picked him up bare handed, he was covered in cat hair, and dropped in back in the tank. That was the last time he tried to get out!!
With all that being said, I'm guessing that a white ribbon eel would be rather close to the blue & black ones. I've never had a white one. Good luck!!
CD