I don't know anything about these guy's but I bought 5 of them yesterday. I usually do not add anything to my tanks that I know nothing about but this was a lack of will/judgment moment at the lfs. Anyways, I added them to my 30 gal tank after acclimating them to my water for an hour (as if they were fish) and then released. They seemed active initially, then after checking back 1 hr latter, they were/are no where to be found. I am wandering if they are nocturnal maybe, or very good hiders? I do have some rock formations they could be behind. There is 3 large Angelfish in the tank but the shrimp were fairly large (larger than some tetra I have kept before with them); could they have been devoured? Thanks.