As the name suggests, the Catalina Goby (Lythrypnus dalli) lives around Santa Catalina Island. It’s about 1/2 – 3/4-inch-long and can be found among the crevasses of rocks down to about 75 meters. It’s considered a nano fish and lives in the west coast waters from California to Peru. They remain gender neutral until they establish dominance within the harem. The most dominant will then become male and grow a longer dorsal fin.