No sand in the QT, yes definitely get pvc for the fish to hide in. It would be better as I mentioned above, to set up the QT and cycle it the correct way, which will take about 4-weeks. After the QT cycle then get the Yashia Goby. But if you want the goby now, then go ahead but it is going to be a ton of work because you are going to have to do daily partial water changes for the next 4+ weeks. Below is a picture of my QT where you can kind of see the type of PVC that I bought at Home Depot. All I have in my QT is the 2-pieces of PVC, heater, HOB filter and thermometer.