Tropical Fish are the most colorful and the overall best in my opinion. There or so many to choose from seawater fish. The problem with saltwater fish is that the water has to be just right on the most colorful and exotic fish. These fish can really cost a lot of money so you don’t want to just go buying a fish tank and filling it with fish until you do your homework first and to ask a lot of question first. 
Then start out small and less expensive until the salt water tank is just right adding the more exotic costly fish little a times to keep from losing a bundle of money getting set up and then finding out how had it is to care for and keep tanks up. With the technology these days keep a fish tank is getting easier but not fully cheaper in the start up. Fish are so cool and calming I love to go into offices with fish in them it just happens you relax and give a since of caring. Dove Medical Press says that fish tanks at the doctors office are a great feature.