The Violet Goby is a large, peaceful fish which has only recently become readily available in the hobby. unfortunately they are difficult to keep and often die since most people who buy them don't know how to properly care for them. The Violet Goby (Gobioides brousonnetti), also known as the Dragon Goby, is an elongate purple Goby which is found mainly in brackish swamps, inlets, and rivers from the Atlantic coast of Georgia to Texas and to the Gulf of Mexico and the northern coast of Brazil. Its normal habitat is mud-bottomed areas of brackish water from one to one hundred feet of water, where it feeds on diatoms (the brown algae so common in aquariums), various sea algaes, small shrimp, and anything else that can fit in its mouth, EXCEPT fish. they thrive on Wardley Shrimp Pellets. Violet Gobies are highly elongate, most aquarium specimens reaching about 14-15in. They are a light violet color and have some interesting tell-tale features. They have a fused pelvic fin which enables them to attach to aquarium glass, much like the mouth of a pleco. They also have a large, trap-door type mouth, like an Arrowana, which is studded with easily visible teeth. Because of their mouth size many LFS and owners alike assume that they are predators and keep them with predatory fish. in fact they have very small eyes .. which should tell you that they are mainly scavengers who put forth only minor effort in searching for food. their primary method of obtaining food is by scooping up mouthfuls of gravel and sorting the edible things from the substrate, then they spit out the substrate and swallow the food particles. they should thus be maintained over gravel small enough to facilitate this. The Violet Goby will mature and thrive best in brackish water -- but they can be acclimated slowly to fresh water and can also be acclimated to fully marine conditions. They do best at temperatures of 72-78*F, but can stand drops to 50*F and jumps to 85*F for short periods of time. they are not particular about pH, as anywhere from neutral to 9 is acceptable. For brackish conditions the specific gravity should be kept at 1.010 but if they have been kept in fresh water when you purchase them the change must be very gradual. a period of two to three weeks would be about right. dragon goby's are a very hardy species and have a lifespan of about 10 years.
igot it from a website from google, typed in 'dragon goby'