Quiggly doesn't look like a normal crew member, but he was born and raised in the fleet so he is reasonably familiar with how the humans do things.  Being extremely non human doesn't tend to slow him down very much but there are a lot of humans who react badly to a hermit crab as tall as they are, a bit wider, and covered in armored plates.

Often literally covered in armored plates Quiggly's shell is very different than that of all the older crabs not born to the fleet, it is built out of pieces of powered armor and arranged to almost resemble  some kind of human construct.