Why do people want to imprison the fish instead of letting it enjoy its life?

When cared for properly, aquarium fish can live full and fulfilling lives. Fish in captivity benefit from routine feedings, clean environments, medical care, and safety from predators. Without the constant stress caused by fear of predation, parasites, lack of food, and harsh weather, captive animals frequently live longer than their wild counterparts. Fish are no exception. Furthermore, many ornamental fish have become domesticated, leaving them unable to survive in the wild. Therefore, an aquarium is not a prison for a pet fish, but rather a safer facsimile of their native environment. In a well-maintained tank, you can see fish freely engaging in a wide range of natural behaviors with little stress.