Some people actually go to tropical islands and scuba dive to observe nature. Here in Orlando we have a different way of doing things. We bring nature to us and then fence it in and add fake lakes, beaches, and rocks. Then we call it a habitat. Then we charge exhorbitant amounts of money to see it. And for those of us who don't fly to tropical islands, we pay it happily. Especially when celebrating the 10th wedding anniversary!!
I worked in an aquarium, and sometimes with dolphins, when I was a teenager. We have come a long way in how marine animals are treated. I won't go all tree hugger on you, but to say that I am not sure that any 'habitat' is really appropriate other than the open ocean. We study the dolphins in captivity and there is important information coming from those studies. But is the cost for the Dolphins too high. I can't answer that, except to say that I try to take this into consideration each time I purchase something like this.