They like ash wood. If you live in the us you can find a dead ash tree that is fallen over on the side if the road and put it in your tank. It will look horrible for 3 months but eventually will look very nice (at the beginning sand the outer wood off so it will cure faster.)
Here is a pictire of an ash stump that has been in my tank and you can see the shavins my royal plecos made.
Here is a pictire of an ash stump that has been in my tank and you can see the shavins my royal plecos made.
