What can i and cant I have for a CUC in Fowlr?

[CleverBs]

I have the following in my tank and am not sure what I can and cannot have for a CUC

Dragon wrasse
Snowflake Eel
marine betta

I dont know if these will kill crabs and hermit crabs. Im sure they will leave snails alone but I am ordering my CUC tonight but dont want to get something thats just going to get killed.

 

[crister13]

That wrasse could rip anything off rocks. Including snails.

 

[CleverBs]

Haha well we will see what he does. He's an aggressive little guy but I love him. Always swimming about. All he wants to do is "play" with my angel and he's very interested in the eel.