Converting my 55 gallon to brackish

Apr 24, 2006
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Nashville, Illinois
#1
I've decided to convert my currently freshwater 55 gallon tank to brackish. The problem is, I don't know how much Instant Ocean to add during a water change using a bucket that's about five gallons-about what people buy dogfood in. Can somebody help me please?
Note: The tank contains a violet goby and many guppies. I don't want to add the Instant Ocean too quickly and make the fish sick.
 

Dec 1, 2007
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#2
The guppies will need to go, they can't live in brackish water, the gobies however will love the brackish water. Instead of the guppies you could get some Mollies, they're very hardy and thrive in brackish water.

You'll need to buy a refractometer so you can test the water, and you don't want to up the s.g. more than .002 a week, it'll kill off all the bacterias in your tank and force it to cycle again. I don't know off the top of my head how much salt per gallon that is, it's pretty much trial and error until you get a system worked out for yourself. At first always add less salt than you think you need and up it slowly testing it with the refractometer.
 

FroggyFox

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#3
Yeah I totally agree...you dont want to just put instant ocean into your tank! I'd mix up a bucket that you know how much is in the bucket (say 2 gallons or whatever) and then measure some IO and see where it gets the sg for you. Then next time you do a water change, add in some SW.
 

Apr 24, 2006
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Nashville, Illinois
#4
What? Why do the guppies have to go? I was told that over the course of a week guppies could be acclimated to a completely marine environment. Now you're telling me that a fraction of that salinity will kill them? Every other source I've heard from said that guppies have no problem in brackish water, so what is it?
Oh and Zombiefetus, I already have a hydrometer. Thanks for the advice you two.
 

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FroggyFox

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#6
um...guppies are not a brackish fish. Not sure where you are going for info, but I wouldn't try that one personally. Try real brackish fish in brackish water...like your goby.
 

Apr 24, 2006
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Nashville, Illinois
#7
Well do you have any evidence? I have seen pictures of guppies in marine aquariums, and two people from the other forum said guppies can live in brackish water. One said they had guppies in a brackish tank and they were doing well. Also, I think it was on the same forum, someone had a bumblebee goby in a brackish tank with guppies to control the guppy population. I have not found one source besides two people on this forum that says guppies and brackish don't mix.
If you do have evidence and guppies can't live in brackish water, what am I supposed to do with all these guppies? I can't cram them into the 20 gallon and the LFS (if they would take them) would have them only as feeders. One of the reasons I got guppies in the first place was because I thought they were brackish fish.
 

FroggyFox

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#8
Just because a fish can survive in a certain environment, does not mean that that is where they were meant to be. I have read that they can be acclimated to in brackish or full marine water...but people don't generally keep them in there. I think maybe part of that is because of the temprament of some of the brackish fish?
 

Apr 24, 2006
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Nashville, Illinois
#9
Well...what does the temperament of brackish fish have to do with whether or not guppies are kept in brackish? The temperament varies from species to species. Like, my violet goby wouldn't hurt a fly but a seemingly harmless bumblebee goby would gobble up baby guppies. I'm not sure what you're getting at so please feel free to explain.
 

FroggyFox

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#10
Guppies do not naturally live/thrive in brackish or saltwater, and as I said I would not put them in brackish water. That is my only point. You are obviously going to do whatever you want, so go for it. I only got in here to tell you to make sure and change it over really slowly if thats what you're going to do, and to make sure that the IO is dissolved completely before putting it into the tank.
 

Dec 1, 2007
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#12
.001 per week is fine, just make sure you don't raise it more than .002 or you'll kill off your bacteria.

Guppies can live in slightly brackish water, but if you intend on raising it more than 1.005, you should really consider rehoming them.
 

Apr 24, 2006
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Nashville, Illinois
#13
Oh that's good. I wasn't really planning on going over 1.005. I need to get my 20 gallon cleaned and put some water in it because I'm going to put my favorite male and a small harem of females in it just in case the brackish water creates problems for my guppies. That way they'll be safe. But, for right now I can't, because it's too dirty and when I put guppies in there they get fungus. I tried treating with Melafix but two died lastnight.
 

#15
I know I'm a little late for this discussion :eek: .... but I thought I'd throw in my 2 cents worth anyway....:rolleyes:

First of all, dont buy a hydrometer, they're not accurate, get a refractometer

Second... dont raise your SG more than .002 per MONTH, any faster and you will cause a new cycle everytime you increase it

Third.... the guppies will thrive quite well in brackish and I have seen them in marine conditions as well.

When I had my 55 Brackish tank up and running I kept guppies as feeders, and I kept them in a brackish tank, couldnt tell you how many times they spawned, but I always had babies popping up in the tank and it wasnt from buying more....
 

Apr 24, 2006
259
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Nashville, Illinois
#16
OK. I'm glad to hear that guppies can live in brackish water. According to my allegedly inaccurate hydrometer, I'm at about 1.003 or so. I've never seen a refractometer before, and my hydrometer was pretty expensive. How much does a refractometer cost?
What ill effects result from moving it .001 a week? I thought the point of waiting a week was to give it time to cycle so you didn't kill off all the bacteria and make it a completely uncycled tank.