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Starting a brackish water Tank

6K views 4 replies 3 participants last post by  iamntbatman 
#1 ·
I've been searching the net and found no guides on starting a brackish tank or the steps involved in converting a freshwater setup into a brackish setup. Can some freshwater fish handle brackish water. How to check salinity of the water etc.

Maybe post a pic of your brackish tank or the fish/critters that live in it.:p



Regards

TM
 
#2 ·
With most brackish water fish, you'll find that juveniles often do well in low salinity or even fresh water, but as the fish grow the salinity needs to be increased, all the way to full marine conditions for some species. The list of fish I can think of that can live just fine in freshwater their whole lives that would also work in a brackish setup isn't long; mollies are the one fish that come immediately to mind though other livebearers might work, too. What fish do you have in mind?
 
#3 ·
Good question. We have brackish water streams and what not here and I was debating on just getting water samples from a few areas and getting them tested. I haven't found a whole lot on line either about them. I think the overall is similar to SW tanks as far as setup and maintenance however the differences are salinity, substrate and stocking. I've seen brackish puffers, as well as a couple kinds of eel that do well in it. Mollies do well in brackish water if they are acclimated properly. I'll be on standby if anyone has answers. I'm afraid I don't retain fish species or technical terms.
 
#4 ·
I think that brackish fish will do well in a freshwater setup. Adding some marine salt may let them feel a bit more comfortable as well as preventing diseases in a FW setup.

I'm not really sure about this but once I trap some fish in the nearby river mouth , I will place them in my pure freshwater setup and see if they show signs of stress or discomfort.

If brackish fish are raised from fry in these setups wont they adapt to a low saline environment?

Does substrate affect salinity of the water? I guess a more fine substrate dissolves more salts into the water?

At the end of the day all tank setups contain salt no mater how insignificant the amount may be.

The only way to really know is to run some tests.
 
#5 ·
There might be some salt in all setups, but even extremely hard fresh water (i.e. with a lot of dissolved salts, but not necessarily sodium chloride) will still not even register on a refractometer. It takes quite a bit of salt to reach into truly brackish territory.

The issue is that, with many brackish species, their bodies are designed to live in fresh water when young and saltier water as they age. In nature, the adults spawn in fresh water and the young slowly move out to saltier environs as they age. Naturally, since the adults do have to swim back into fresh water to spawn, brackish water fish have a great deal of rapid adaptability to different salinity levels. However, for the long-term health of the fish, it's best to try to replicate what they would live in in nature. For example, Figure 8 puffers kept in moderately brackish water grow larger and live considerably longer than those kept in fresh water, which reflects the lifestyle of the fish in the wild.

Also, most substrates are inert and won't affect salinity. Some are calcium-based (crushed coral and aragonite sand) designed for use as substrate for African rift lake cichlids or saltwater, but these won't make your water more salty.

As for how to set up a brackish tank...well, it depends on how brackish you're talking about. A tank that will ultimately be only low end or moderately brackish could be set up very similarly to a freshwater tank, with rocks, driftwood and plants like java moss, java fern and mangroves. High-end brackish would be different still, and many "brackish" fish do just fine in full marine conditions as adults so at that stage the tank could be converted to a more typical FOWLR type setup.
 
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