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Re: Salt concentration.

Subject: Re: Salt concentration.
by Otter on 22/7/2009 8:41:42

Orfe are said to be more sensitive to salt than koi or goldfish, but I'm not sure what their limits are.

I'm certainly not going to dose it to anywhere near the concentration of sea water and I'm not entirely convinced that salt is bad for freshwater fish.

I understand that you're not going to try to turn your pond into the ocean, but why raise salt above the level for which the fish evolved? I know many people add low levels of salt as a matter of course, and it doesn't seem to be doing too much harm. But does it really do that much good in the long run?

I think the reason for the conflicting opinions on this one is that the effects are subtle and the subject has never been adequately studied. Whatever theory you believe, it's easy to interpret what you see as confirmation. I claim no certain knowledge. But if it isn't broken, I'd rather not try to fix it.

You need to forget the word salt and think in terms of osmotic potential.

I've forgotten enough already. But whether it's salinity or osmotic potential, I think the ideal is still as close as you can get to the environment the fish would have in the wild. There should be no osmotic stress for a healthy fish in the sort of water for which it was born.

Now, I agree that if a heron puts a big hole in one of your fish, some salt might help the fish maintain equilibrium until it heals. But one trouble with using medications all the time is that the fish and their pathogens will adapt to the drug, and then the it won't be as effective. I honestly don't know how big a factor is that with salt, but some of the "experts" believe that it's better to wait until you actually need salt, and that makes sense to me.