Ahh I see. Well we will have to agree to disagree on that one. There isn’t a great definition (which means were both right, YEA US!) for nano that I have found the reef guys will tell you 30 gallons or less. Some would call the tiny ones you can hold a Pico. I picked it for the nano-scale definition, and from the Greek word, nanos, meaning dwarf.
But hey live, and let live.
What kind of shrimp do you have? I have a 12 gallon that’s almost all CRS. My little girl calls it my fairy garden because they seem to fly around. I think they are great for the plants as well. I would theorize that the shrimps constant grazing could stimulate the plants sort of in the way people say singing or talking to plant do. Ha! I don’t know maybe that’s crazy. There are all sorts of variants on the CRS shrimp also in yellow and white and a few more I think. And they can't be kept together or it will mess up the genetics (color wise). So that’s another good excuse to get more of them.