The Lagoonarium is a lagoon, so it's saltwater, but it is fenced so that you can swim with sharks, rays and fish in somewhat shallow waters. I did not find it cruel at all.
As to adapters, there are standard US plugs in the room. I brought a 6 strip surge outlet so that I could plug in my camera's battery charger, cell phone charger (I do have to call home everyday and T Mobile works there on the VINI network - the cellphone company of FP)and my hairdryer at the vanity. Was very happy to have that.
Also, a staple LCT favorite for travel is the clear plastic over the door shoe bags. The closet in the standard room is more of a cabinet. I was very glad to use that for shoes and accessories. They travel flat, you leave them behind on the way home.