Unfortunately, the weather in Florida was hot and about half of them died before they got here. The seller threw in some bonus items (pipefish and larger shrimp). Those succumbed as well.
Of the grass shrimp that survived, several jumped out through the mesh lid of my aquarium, many were eaten by my fish (pajama cardinals, starry blenny, dartfish, and maybe even the mystery wrasse), about 20 were hanging out on the back wall of the aquarium but have since been eaten or relocated, and a handful have been spotted hiding in my rock.
The seller is sending me some more to make up for the loss. Apparently, the weather is cooler there this week. So, hopefully we'll get a better mortality rate.