Depends on what age you buy them at, i would say. At less than 1cm they would be a snack for many fish if they fitted in their mouths... Amano can, and do, get to a relatively large size though, so if you were buying then when they were at a bigger, more suitable size then i don't think they would be an issue.
My female Amano is 4-5cm long, about 3 years old, if that helps at all !?!?!