I have found my fish get into the most amazing places... Sadly it is often fatal, but impressive nonetheless. Can't say how they do it tho.... I once had a mating pair of Golden Dojos (hard to do) that my wife named Sonny and Cher. Well apparently Cher was an adventurous type and she would get into the overflow and down into the sumps I had for my large aquarium. One day I lost power and the sumps were off for over a day. When I started them back up I found that Cher had once again made her way down while everything was still running. Because I hadn't noticed and there was no water running she was dead by the time I found her. Makes me sad even now.....
as for for the scuds, I have bought mine off aquabid a couple times, although usually one purchase will keep you going indefinitely if you culture. If they stay in your sump and eat detritus of various sorts you'll get a nice cleanup crew, they'll essentially maintain themselves and they are kinda fun to watch.
If if you don't want to buy I would think finding them locally would be feasible, but I'm in NJ and can't really speak intelligently about where to go in WA. If you have a small lake or pond nearby then I'd be shocked if you didn't have scuds nearby. Of course the usual issues about harvesting from natural sources come into play such as disease. I wish I still had my scuds going--I'd just send you some.
One additional note: I'd describe a scud more as a very tiny shrimp, although I can see the flea analogy. In fact, I think a scud is a relative of shrimps, but I'll defer to those with much greater biological knowledge than myself.
