So by blind, stupid luck, I went and looked at my tank around midnight Saturday night. I saw a peppermint shrimp walking along the bottom, but acting differently than usual. I grabbed a flashlight, and sure enough, the shrimp was carrying eggs. She walked back and forth across the tank a couple of times before swimming up to the surface and releasing the eggs. There was just this explosion of larvae! I couldn't believe how many there were. Unfortunately, with the circulation system going full-bore and me being completely unprepared, I didn't get a chance to try and collect any of the larvae, but it's nice to know the shrimp are busy making shrimplets.