I'm new to shrimps, and have a quick question. I will have a number of cherries in a 30g and wanted to put two species in the tank. I thought the green shrimp would go nicely, but no luck in finding them. What other species would co-exist with cherries without getting frisky with them?

Tap water in Houston is naturally 8+ ph and hard as a rock, so I was trying to stay away from soft water/low ph species. I have some crystals in a planted tank that I keep at 6.9, but that is with CO2 (I keep an eye on them to make sure I'm doing no harm - they seem happy).
Your advice would be appreciated!!