Starting A Brackish Tank

[HeatherSwaby]

Hi, I am new to this forum.
I am about to start up a brackish tank, I am new to the hobby and have only ever had coldwater fish before. I have been to my local aquatics shop and they are selling puffers and bumblebee gobies in freshwater. How do I acclimatise the fish from fresh to brackish? Oh and i am looking at a figure 8 puffer with some knight gobies.
Thanks

 

[iliveinazoo]

Hello HeatherSwaby,
Brackish is little different to freshwater especially at the salinity that you will be running this tank at, say SG1.03@25 DegC.  The best advice is to start the tank of at the same salinity as the dealers tank that your fish will be coming from.  If they are coming from fresh water then you can cycle fresh and up the salinity once you have the fish.  You can adjust the salinity adding more or less salt as you see fit, there is a general rule that you should not adjust the salinity by more than SG0.02 at any time to avoid killing off much of the nitrifying bacteria in your filter.
 
You will need marine salt (not aquarium or tonic salt) as that contains the other minerals required not just sodium chloride.  You will also need a hydrometer or refractometer, refractometers are more accurate but since you are keeping brackish fish as opposed to marine then personally I don't see any reason for the extra outlay.
 
Figure 8 puffers are lovely fish and I have one myself but a Knight Goby will most likely predate a Bumblebee Goby so I'd recommend choosing one or the other.
 
Are you fishlessly cycling or can you obtain filter media from a friend?

 

[iliveinazoo]

Re-read my post tonight and noticed that I missed a zero from the numbers, they should read 1.003 and 0.002

 

[HeatherSwaby]

I had the tank from a friend, and it came with lots of rocks ect. I have kept the rocks in but replaced the gravel with sand. I am going to be getting some live rock in a week or so, I am just waiting for it it be cured.
I actually posted this thread a few days ago and I have since added salt to the water before seeing the reply as I wanted to get the cycling started....
I wont be buying fish until the end of the month or when the readings in the tank are ok. Is there another way I can introduce the fish from fresh to brackish? Or should I just empty my tank and replace with fresh water?
Thanks

 

[iliveinazoo]

what SG have you started with? Figure 8's prefer lower salinities, far lower than live rock will tolerate so unfortunately the critters on your cured rock will die and pollute your tank.

You can drip acclimate fish to different salinities which is basically adding the water from your tank into the bag that the fish comes in slowly and in stages to gradually acclimatise the fish to your tank conditions, it could be done in the bag or in a bucket.

Are you adding an ammonia source to cycle the tank?