The Catalina Goby, though kept by many in warm reef aquariums and considered to be frail, can actually make a hardy captive when kept in more appropriate cooler water environments.
Catalina Gobies frequent areas strewn with rocks or boulders, and are found at depths between 0 and 200 feet (0 to 60 meters). In captivity, they are somewhat territorial toward each other. However, due to their small size, a pair can be kept in moderately sized aquariums. Be sure to provide plenty of hiding places for them. Catalina Gobies normally get along well with other fish and are considered to be reef safe. The main concern in a community containing Catalina Gobies would be the lower temperature requirements of these fish, and the possibility of their being bullied or eaten by larger or aggressive fish. Many people maintain that the Catalina Goby will thrive most easily, and be shown to its best advantage, when kept alone in an aquarium with invertebrates.
A mature Catalina Goby is usually around 1 inch (2.5 centimeters) long. They are brilliantly colored in blue and red hues. Most of the fish is a bright orange-red color. Toward the head, vertical blue bars appear, and the head may be almost entirely encompassed by a large band of the bright blue coloration. Like most Gobies, Catalina Gobies have elongated bodies with relatively small fins.
Catalina Gobies are native to eastern Pacific regions, and are most commonly found in the Gulf of California. They are often sold in the pet trade as warm water fish; however, when kept in warm environments their mortality rates are higher. Catalina Gobies may be quite disease resistant, and may live for years rather than months, when kept in appropriate, cooler temperatures.