I've always thought that it had more to do with the oxygen levels in flowing water, rather than the food. After all, food is easy for a shrimp to find in non-moving water (there are microorganisms to pick off of every available surface in an established tank), so going out of their way to do so much work must have a benefit other than just dinner.
I think they're a bit more similar to those funky little Hawaiian rock-climbing gobies. XD Salmon jump. Shrimp and gobies cling for dear life to the wall while the current tries to sweep them away XD
Time to get creative again. They are definately a new species....blue salmon shrimp. There were a few on the outflow but....there were more in the filter box. I watched them climb up on the outflow, through the current, up and over into the box! Really?? As if you don't have enough food and what have you INSIDE the tank. Time to break out the plastic grid material and make a fence to block the enterance (which should actually be the exit ).