This is a question heard all over the Internet including many fish forums and many questions and answer types of sites. The biggest reason that many people find themselves asking this question is because many pet stores, local fish stores, and even Walmart stock and sell these fish as freshwater fish. This often leads to confusion and issues after a person has bought the cool looking fish and brought it home.

The Simple Answer.
When you lay down the facts and look at it from all views the answer is, "No!". You can't keep a brackish water fish in a freshwater setting. The freshwater causes all sorts of problems and you never know when one of them could hit your poor dragon goby (or dragonfish as it is often called).

The Complicated Answer.
Dragon gobies are found in estuaries that connect freshwater resources with the ocean. Most of the time it stays in brackish water that has a salinity between 1.005 and 1.012. However, they can move into water that is fresh and even down to water that is ocean water. This is done every now and again in nature. When these fish are caught they are then acclimated to freshwater and sold as freshwater fishes. They can do fine this way for some time, but one day that may very well change!

The Acclamation Process.
If done slowly your dragon goby can be acclimated to freshwater (though it is likely that this is how you bought him) and even salt water. To acclimate the fish you slowly change the conditions with which he or she lives. It should take two to four weeks to go from one type of water to another with the larger extremes (fresh to saltwater) taking four weeks. These changes can be made and the fish will do fine, however they can't stay that way long term.

Why Not?
There are accounts all over the Internet of people keeping these fish in freshwater long term. Their success may have you thinking that it is acceptable and will work out fine for you. However there are a huge number of reasons not to do this!

  • Shorter life span. Dragon gobies can live at least ten years with some living even longer than that. However, this is in ideal conditions. In freshwater their life span is significantly lower. Some report their gobies living long lives in freshwater with those times being between 3 and 5 years. Do you really want to result in having your goby live half his natural life span (or less) because you are keeping it in freshwater?
  • Never know when problems will arise. Some dragon gobies will live for years without any problems showing up in their freshwater homes. Then one day you will wake up and there will be a problem.
  • Swollen tissues with red or pink spots. Many times dragon gobies in freshwater will get sores on their gills, around their fins, and even in their mouths. Over time this can become a huge problem and result in death. This is often one of those problems that shows up unexpectedly.
  • Slime. Another thing that some people wake up and find is a grayish colored slime covering the body. The dragon goby needs the salt and other minerals found in brackish water to maintain healthy skin and can develop a slime that clings to their entire body if they aren't kept in an appropriate home. This often leads to death as well.
  • Lower immune system. When in fresh water the dragon goby has a lowered immune system. It is more likely to develop fin rot when it has injured fins, develop a fungus, develop a bacteria infection, and even get parasites. This can cause issues with all the fish in your fish tank and can make the other fish in your tank sick as well.

With all of these things that could go wrong, it just isn't worth it. If you need to you can leave your goby in freshwater for a short period of time. You should add at least a little aquarium salt, but you also need to make sure that adding salt won't harm the other fish that you have in the tank.

The Best Option.
The best option you have is making sure that you can offer your dragon goby the perfect home for him. Check out this article, The Dragon Goby, for more information on setting up a great home for the dragon goby and feeding it a wide variety of good foods. You can also check out The Dragon Goby: Tank Mates to find out who you can put your dragon goby with.

Understanding where the dragon goby comes from one can see why the dragon goby can be sold as freshwater fish. If they were ones that looked ill when placed in freshwater than no one would want them. On the other hand, it is really important that they have a brackish water home that is complete with marine salt and not just with aquarium salt. This is the only way that you can avoid health problems down the road and give your dragon goby a long life.

I Have a Dragon Goby in Freshwater, Now What?
If you have purchased a dragon goby without really knowing about the fish you have a few options.

  1. Set up an appropriate home. Your dragon goby would love to have a great home at your house. He or she needs a large tank of at least 29 gallons (preferably 55 gallons) and it needs to be brackish water with marine salt at a salinity of at least 1.005. Make sure that you acclimate them to an appropriate salinity over a couple of weeks. You can't keep all freshwater fish at this salinity, so you will need appropriate tank mates as well.
  2. Take him back. If you can't set him up with a good home then you should take him back because he won't do well and you won't know when the good times will end.
  3. Give him away. You can also give him away to someone who has a brackish water tank, who is looking at setting up a brackish water tank, or who can.

Unfortunately you can't listen to the accounts of it being okay. You just have no idea how long it will be okay for and one day okay may turn into a horror story. Instead you need to make sure that you do what is best for this fish and give it the home that it deserves.