Brackish pond

Has anyone here ever had a brackish garden pond? It doesn't seem like it would be too difficult if you picked hardy fish.

People have talked about it before on various pond forums, but I've never seen one.

That's the first thing that came to my mind. On the forums where I've seen people talk about it they also mention temperature swings as the other major issue. There are species that can handle large salinity swings, but as the salinity goes down osmoregualtion produces more waste - I'm paraphrasing so forgive me if I'm butchering this concept, I'm not a scientist.

I think the salt might get expensive if you want to maintain salinity levels. There's a lot to consider, if I ever tried something like this I would probably need some guidance.

I've also considered a brackish pond, actually a brackish stock tank, but abandoned the idea due to the cost of salt. I figured that I would need at least a 100 gallon tank for temperature balance, but I already had a 55 gallon brackish aquarium indoors with the added benefit that I could see the fish better. I never got far enough along to consider the problem of rainwater dilution, but that would be a major problem along with overflow during rains ruining the soil with salt around the pond or stock tank. 

Phil Nixon

Central Illinois

I don't think that species like Gambusia, sheepshead minnows, or mummichogs, for example, would have a problem with rainwater.  It would require a hurricane or a major storm dumping many inches of water into the pond (including runoff into the pond) to have any substantial effect, or, a lot of freshwater in a very short time.  An inch of rain wouldn't cause that much of a fluctuation in salinity.  Salt doesn't evaporate, it stays in the pond, just like an indoor tank.  You would have to have the pond contained so that runoff rainwater could be kept out.  I don't think that the water and salinity changes would affect the fish that much, but, siltation or the addition of leaf litter and such could change the chemistry of the tank, muddy up the water and visibility, and clog filters, etc.  Those species are very hardy, they can take large changes in salinity just fine. I'd worry more about predators eating the fish more than anything.

Now, there could be other reasons for salt disappearing, but, if the pond is lined, or water escaping the pond (other than evaporation), then I can't see how that would happen.  A severe drought would increase the SG, but, that would occur over a long period of time, and the fish will adapt.

I think a bigger concern in Maryland is if the pond what to do in the winter.  You'd need a heater, maybe a circulation pump or airstone and some way to keep the pond from freezing solid, so it would need to have some depth.

Thanks for the input, there's a lot to think about. I don't think it's something I would try in the near future but who knows. Would the salt make a big difference in freezing temp? That could help with winter freeze over maybe.

Yes, it would take longer to freeze, but keep in mind, that even the Chesapeake Bay has frozen over in the past, as have the brackish (albeit less brackish) waters surrounding Washington DC.