Why? Well the fish I keep come from areas of the reef where there are lots of hiding places areas to escape and chill out with lots of places to seek out and sleep at night with little competition for those places. I believe my reefscape with lots of rock with caves and overhangs give my fish lots of places to get away from it all should they wish and lots if choice to sleep at night. I keep Damsels blennies dwarf angels small wrasses and the like which like to stay near the reefscape and are not open water swimmers. I believe this in turn not only gives them an environment they are familiar with but reduces stress and makes fir healthier fish not just in body but in mind.