I was thinking of burying a short length of PVC horizontally in the substrate with 1 open end sticking out, just below a piece of drift wood, as a shelter for loaches. Has anyone tried this, and will loaches or other bottom fish make use of it?
I have some larger vinyl tubing underneath my substrate and the loaches hang out in there all the time. They come out to do things, but they sleep in there. When they're chasing each other around the tank, they also go zipping through the tube too.
I use PVC in quarantine and hospital tanks, since it's so easy to clean and makes the fish comfortable. If you want to leave it on the substrate, but don't want to see the stark white piping, get some aquarium sealant and matching gravel. Coat the pipe and roll it in the dry gravel, let set for 24 hours. It will blend in with your substrate, and still provide great cover for the fish.