I didn't have any for years, never even saw one in person until I started a refuge and bought some macro algae at LFS. Now those little @#$%'s are everywhere.
then they came on as a hitchhiker..which i understand, i was just curious, if months or a year or two go by (without adding anything new) would these little bast*rds pop up?
The ones in my tank grow pretty fast. I can't imagine a small one would hide for a long period of time before being seen. They also propagate like flippin rabbits. If you have one and it is hidden well so you can't see it, you would definetly know it in a few months at least by all the little ones popping up all over the place.