They don't need sand but need cover (net would be better) on aquarium top as jumper it is. Calm aquarium will help in adaptation phase.
They can be very timid and skittish when first added, so depending on how much "attention" they recieve from your current inhabitants, could have a lot to do with how they adapt.
Within the 1st couple of weeks of being collected they are susceptible to decompression issues. They also seem prone to bacterial infections during this stage. Once they get past the first few weeks they are quite hardy and outgoing.
Agree with all this, would also add that my two purples came in loaded with flukes. I did a series of FW dips that took care of the problem and they handled them fine.
My last purple also had flukes. Treating with PraziPro took care of that. Tank must be covered tightly with a min of 1/4" screen mesh. My last tile fish even managed to get just its head through the 1/4" mesh and I found it hanging there dead.