Security update: Darios are definitely not shrimp safe.
I fed mine in the morning. A couple hours ago I put a bumblebee shrimp in the tank, about 3/4", within a bush of plants, to make sure they didn't see him swimming right out. Watched for about half an hour. Finally one noticed the shrimp, and in their usual way, approached slowly, then stared hovering by, and after a couple minutes, started picking. The shrimp tried to escape, the fish followed, then tore a limb, spit it, chased again, bit the swimmerets, fatal blow. Shredded the shimp and ended with a mouthful. the other 2 joined, one took a bite, the other wasn't interested in the dying body. After that, they didn't scavenge the remains.
These guys are tiny beasts. Shrimp survival will depend on the mood of the fish, cause there's nowhere they can hide from them.