even in a bare bottom tank rays STILL pump the tank base like they should be doing in substrate
you only have to look at the design of a ray to tell you they need substrate
why do the rays have the sticky up eyes its so when they are covered in substrate they can still see preds yes or no
you only have to look at the design of a ray to tell you they need substrate
why do the rays have the sticky up eyes its so when they are covered in substrate they can still see preds yes or no



yes sir 
