Brackish water?

Question
I would like to buy a dragon goby (dragon fish/ violet goby). They are tropical fish and live in brackish water and need sand instead of gravel in their tank. I read in other sites that freshwater fish can survive in brackish water. I would also like to buy a koi fish and maybe some goldfish. Will the gold and koi fish be able to live in brackish water? Tropical water? Will the sand in aquarium affect them at all? I have three 10 gallon aquariums. If a 10 gallon aquarium isn't big enough what size of a tank should I have? I would like the dragon fish most of all, so if the koi and goldfish won't be healthy in the dragon's environment, what fish do you recommend with a brackish dragon goby? I would like to know as much as I can before I purchase any fish. Thank you!

Answer
Hi Kami,

The Dragon Goby is going to be way too big for your tank.  It requires a minimum sized tank of 50 gallons.  http://www.liveaquaria.com/product/prod_display.cfm?c=954+2526&pcatid=2526

It is going to be too big for a 10 gallon tank.

I recommend salting the water to 1.010, as that is what mine do perfect at.  Half saltwater, half fresh.

Although some freshwater fish may live in brackish, I don't recommend it.  Adding a teaspoon per gallon to any kind of freshwater fish is okay for most, and it will support the anti-parasitic properties, as well as anti-bacterial and anti-fungal, but it is not recommended that you go above that.  So, mixing fresh and brackish fish is not recommended.

Goldfish are pond fish.  Each requires 25 gallons, and after it is 5" long, (they get to 14"), it will need a pond or a huge aquarium.  At least 50 gallons EACH.

Petstores won't tell you this.  They will sell you a fish and let you put the poor guy in a tiny bowl.  Bettas, goldfish, the likes are often abused terribly by unsuspecting pet owners who believe it's okay to keep them in cups and bowls and tiny aquariums.

Furthermore, the water quality gets very bad when a goldfish is in it.  It is one of THE biggest poopers there is.  Just to support a baby goldfish (1" long), the water has to be five gallons, with a huge filter on it, rated to much more.  Otherwise water quality suffers.

Your beautiful goby will need a larger tank than you might have thought about.  Perhaps you have a craigslist.org in your area?  I just saw one on ours for $100.  A very good deal!  Came with the filter, lights, everything and you can find a similar deal.

I do caution, if that tank is not freshly washed with bleach in the water, to wash all used items thoroughly in a bleach/water solution to clean out any other fish diseases if you buy used.  Many people sell used tanks because their fish died of something.

Sand in the aquarium will not hurt brackish water fish.  It is recommended to use real sea live sand.

Another goldfish/goby issue is the goby is going to eat your goldfish.  They have big mouths and love eating fish.

Good luck Kami and I hope I've answered all your questions in a friendly fashion.

Please rate me for my answer.  I volunteer to help prevent disasters in fish-keeping and to help those who are already experiencing them.  Not always do I get to warn someone about the sizes of fish before they purchase, as in your case, so perhaps this will help you make a better decision down the road.:)

Happy fish-keeping!

Renee