How small is too small for eel tank mates?

[Nuclear Queen]

I'm considering putting a peacock eel or a black spotted eel in a community tank, but I know they can see smaller fish as food.
What counts as "small" when referring to things could be mistaken as provided food to the eel? Are we talking molly small, or baby tetra small?

 

[josh7]

I think anything under 1.5 inches could be considered food for a peacock eel.