oh haha all mid sizes... my tank plants are different from the ones u guys use... mine mostly are pretty "long plants" with either slim or large leaves... so ya they can dart right through the plants to the back of the tank. there is only 1 or 2 drift wood in it.
like bro cjh has said, yes they are exception. depends on where u got your discus from. if u got it from normal freshwater fish shops, the fishes maybe for quite awhile, so they are kinda used to the usual movement. if u got your discus from breeders, like the ones i used to have, the only humans that the discus may have seen is me and the previous owner.. so they will be alittle more timid.
but off course getting discus from breeders u will have more fishes too choose from