They will eat ANY fish that they can swallow.
Not true. Snowflakes are nearly 100% crustacean feeders. A small fish such as a 2" six line wrasse is much safer than a 3" blood shrimp. Technically, they are reef safe, but it is not advised. They will burrow in the sand, topple rock, etc. They won't harm sessile inverts, but crabs and shrimp beware! Bo
PS, a 55g would be perfect for a snowflake or similarly sized eel.