Can violet gobies be kept in freshwater or not?

Question

I have had a violet goby (in freshwater) for over a year now. I'm worried that if I try to convert the tank to brackish water, I might do it too quickly and kill everything in the tank. I also don't know if my guppies (normal, not fancy) can live in brackish. I've been all over the internet looking for answers but there are so many sites that contradict one another. And besides all that, I have a silver dollar and he could use more room. (The violet goby's tank is bigger.) I'd love to hear from anyone who has kept violet gobies in freshwater successfully or has had problems because of freshwater conditions. Thanks.

Hey Copperhead, when you say salt, do you mean regular medicinal aquarium salt, or do you mean the widely recommended Instant Ocean? I'm not trying to tell you to use Instant Ocean. I just want to know if you or anyone else has had success without it.

Answer 1

Guppies are like goldfish and are really hardy. And although they normally live in freshwater aquariums, a little salt probably won't hurt them since they are hardy fish. So they should be fine. I am not sure about the goby or your silver dollar. But i have had both types of tanks and i believe that freshwater tanks are easier to keep. You don't have to worry about the salinity content of the water, and the temperature. And most fish sold in the pet stores live in freshwater environments. So thats my take on it. Hope everything will work out for you!

Answer 2

I've always kept them in brackish (1 tablespoon/5 gallons up to 1 tablespoon/gallon), but one time where I worked in a pet store, we had them in freshwater, but they all developed body fungus and died. They don't require a lot of salt, but from my experience they do benefit from having it in their tanks. The same with guppies and mollies, although plenty of people have also kept these successfully without using it. Guppies can actually live in full marine conditions if the salinity is raised over a period of about a week, so don't worry about them in the amount of salt needed for the goby. (photo of my guppies with mushrooms, zooanthids and ricordea in a quarantine tank: http://s172.photobucket.com/albums/w10/copperhead_photos/?action=view¤t=DSC00008.jpg )

I think I may be able to give you some idea as to why you're seeing conflicting answers. A good many brackish fish don't spend their entire lives in a specific concentration of salt. May spawn in either freshwater or saltwater, and some even move between environments on a daily basis. So some of the answers you've seen may be based on the information of where one person has seen the fish over another's, or the age of the fish. For a fish that's adapted to having some amount of salt in their water, they may not be able to extract it as efficiently as fish that live in freshwater environments where the concentration is much lower. Therefore they have to put far more energy into extracting salt (which could otherwise be used for fighting disease or growth), or be stressed by improper salt-fluid balance in their bodies.