The Dragon goby (Gobioides brousonnetti) is also known as the Violet goby due to its purple body color. It will do best in a brackish aquarium, but can adapt to freshwater conditions if the acclimatization process is allowed to be slow and gradual. Dragon gobies are sometimes kept in marine aquariums, and the same thing is true here – a slow and gradual acclimatization process is necessary.
The Dragon goby can grow up to 24 inches long in the wild, but aquarium specimens rarely exceed 15 inches in length even as adults. The body is elongated with a large mouth, and the Dragon goby is therefore sometimes compared to the Arowana fish. The mouth of the Dragon goby is trap-door shaped and the teeth are very evident. Just like the other members of the Goby family, the Dragon goby is equipped with a disc-shaped sucker that it can use to attach itself to corals, rocks and aquarium glass. The sucker is actually a pelvic fin that has fused to become a sucker.
As mentioned above, the Dragon goby should ideally be kept in a brackish aquarium. Its native environment is brackish swamps in Florida and regions where rivers empty into the sea. Today, you can find wild Dragon gobies from Georgia to the Gulf of Mexico, and there is also a breeding population living off the northern coast of Brazil. This fish loves muddy waters with mud-covered bottoms.
A common misconception among saltwater aquarists is that the Dragon goby is a capable predator that should be fed feeder fish or live shrimps in the aquarium. The truth is however that the Dragon goby is a scavenger and wild Dragon gobies spend most of their time looking for smaller food particles near the bottom. The Dragon goby feeds by filling its big mouth with gravel or mud and search through it in hope of finding something to eat, before it spits out the substrate and grab a new mouthful. Bloodworms, daphnia and plankton are more suitable foods for your Dragon goby than feeder fish or large shrimp.
The adaptability of the Dragon goby is not limited to variations in salinity. This species can adapt to a wide range of different pH values, water hardiness and levels of organic waste as long as it is not exposed to rapid changes. The pH can be from 6.5 to 8.5 and the recommended temperature range is 72°-78° C. Dragon gobies have however been found living in waters where the temperature has been no higher than 50° F, while other specimens have endured temperatures up to 85° F. The Dragon goby is very sensitive to ammonia, and keeping the amount of ammonia down is therefore even more important than keeping the levels of nitrite and nitrate down in the aquarium. If your Dragon fly starts gasping for air at the surface, you should check the ammonia levels in the aquarium. If high levels of ammonia are not counter-acted, the Dragon fly will eventually die. A Dragon goby that is housed in a well kept aquarium can live up to 10 years or even longer.