nudibranch

So I got a shipment in from the gulf region of florida and found a nudibranch. That's as far as I can get. It's not wearing a hat so I can't tell if it's a black hat or a white hat (dark side of the force or light side of the force for those that don't get the hat reference [ bad or good for...

I just found these little guys all over my refugium, hoping someone can let me know what they are and if i should start removing them. Thanks ;)