I currently have a 17" snowflake in my 110g reef.
I have learned not to keep fish and shrimp small enough for him to eat.
If it fits in his mouth he will try to eat it.
This is about what I have lost since I got him:
(4) green chromis
(6) peppermint shrimp
(2) cleaner shrimp
True percula clownfish (2")
Picasso clown (2")
And a handful of small damsels
At first I just didn't know what would happen to them, I would wake up and be missing a fish, I eventually figured it out.
As long as you keep him fed good, once every three days, 3 silversides, then he shouldn't be too hungry and try and eat a fish