HI:
Thanks for the question.
I don't have any direct experience keeping these two together. I would guess that cleaners are fine w/ fish.....as long as... the fish are brought into the cleaner enviroment and the cleaner has set up a cleaning station. If you add a cleaner shrimp to a tank w/ an established eel and the shrimp is wandering around the tank looking for food, my guess is the eel would eat them.
This is different than adding an eeel to a tank w/ established shrimp.
My case in point is my lions tank. i have never added cleaner fish or shrimp to my tank and many of my lions are many yrs old-ergo they have never seen or used cleaners in the wild. When i did try to add a cleaner shrimp, the lions went and immediately tried to eat them.