Tropical fish include fish found in tropical environments around the world, including both freshwater and salt water species. Fishkeepers often use the term tropical fish to refer only those requiring fresh water, with saltwater tropical fish referred to as marine fish. Tropical fish are popular aquarium fish, due to their often bright
coloration. In freshwater fish, this coloration typically derives from iridescence, while salt water fish are generally pigmented. Tropical fish kept for home aquaria include the following: Recreational SCUBA divers are often enthusiasts of tropical fish as well. Some keep lists of fish species they have observed while diving, especially in tropical marine environments.