Zebra eels are sometimes kept in reefs. While shrimp and such will still be at risk, it's generally somewhat less of a risk with a Zebra. They do get pretty darned big, and there is a risk that their hiding in the rocks can cause a rockslide if your structure isn't sound.
Lids are a must for any eel in any tank - those jokers WILL jump.
I had a customer keep a Zebra eel in a 90 without any issue, for about 5 years, until it got too big, then he traded it in and we rehomed it to a larger, FO tank.
Jenn