I concur with Lotsoffish - I have kept Rummynose for several years now - and once you get them settled in your tank, they are fine. But they are all wild caught - and as my LFS says - they ship horribly.
I have seen my LFS scoop out 20 to 30 dead fish at a time from a tank filled with a one to three day old fresh shipment.
their advice to me - and so far, it has worked fine - is let them get a shipment in, and wait at least 2 weeks. Then buy the Rummynose after those 2 weeks - and spend double time what you normally do acclimating the fish to your tank.
IE - lights off, float the bag, add water to the bag several times more than normal, etc. then net the fish and release them in your tank. Following that regimen, all my Rummynose have always adapted to my tank quite well and quite quickly