Fresh and saltwater fish make excellent pet companions for people that enjoy watching marine life. As all fish are beautiful and fascinating to watch, saltwater aquarium fish are often preferred over freshwater fish because they tend to have brighter and more vivid colorings and have more interesting habits to observe. Fortunately, for aquarists seeking saltwater fish as pets, there are plenty of fish and other marine invertebrates to choose from as there is an abundant array of farm-raised saltwater fish for sale. Chosen as pets for their fascinating spikes and graceful movements, lionfish, such as Radiata lionfish, Dwarf Zebra lionfish and Black Volitan lionfish can be harmful to other saltwater fish within the same tank as they are semi-aggressive and have venomous spikes. Black boxfish and Cubicus boxfish are often selected because of their comical box-like bodies, puckered lips and exotic polka dot patterns; however, they require expert handling as they are known to release toxins if stressed. By learning more about the various types of saltwater fish for sale, you can determine which fish can peacefully live together in your aquarium.