I’ve heard this behavior has to do with them being stream critters. In the wild they’d look for a faster moving patch of water, get as high as they can, and swim or fling themselves up stream. I’d make sure the can’t jump out of the tank over there, but it’s not a concerning behavior (well besides possible suicide…)
Just shrimps doing shrimps thing. My cousin even found one crawling on the floor 12′ from the tank 🤣 if everyone hangs out near the surface then there’s a problem with the water, if some it’s fine
BurntHam_ 
I’ve heard this behavior has to do with them being stream critters. In the wild they’d look for a faster moving patch of water, get as high as they can, and swim or fling themselves up stream. I’d make sure the can’t jump out of the tank over there, but it’s not a concerning behavior (well besides possible suicide…)
Just shrimps doing shrimps thing. My cousin even found one crawling on the floor 12′ from the tank 🤣 if everyone hangs out near the surface then there’s a problem with the water, if some it’s fine
if they’re by the surface i’d assume something caused the dissolved oxygen to decrease, which is why they’re close to the source …?