What Is The Deal With Aquatic Salt?

[PaulQ]

I keep reading here and there that some fish like aquatic salt added to the water? I have a freshwater tank. Should I be adding salt to the water? Does it depend on the fish? What if one fish likes it and another doesn't?

The last fish I looked at where it said this was a mollie.

I have a 26 gallon tank.

Thanks!

 

[hihi100202]

No do not add salt, the salt is for saltwater fishtanks only.

Some fish like a small bit of salt, but not that much. Just do not add any salt

 

[OldMan47]

Salt is a treatment for certain diseases. The aquarium salt sold in a pet shop is the same thing as you have on the kitchen table except that it has no added iodine and has no "anti-caking" ingredients added. In almost any case, you can keep it on the shelf in case of disease in your tank and do not place any at all in the tank itself. If you have one of the rare fish that do better with a bit of salt in their water, it is not aquarium salt that they need. Instead they can make good use of the salt that is sold for a typical salt water tank. These are brackish fish that need something between fresh and salt water. Some few of the gobies fall into this category of fish. Some people will advocate the use of salt for mollies. Pet shop mollies show an amazing tolerance for salt water salt but are fresh water fish that do fine without it. At one time reef keepers used pet shop mollies to cycle their tanks the way we might use zebra danios to cycle a freshwater tank. Because mollies were so adaptable to salt, they would survive and even thrive in a pure salt water environment.

 

[PaulQ]

Interesting! Thanks! No salt!

 

[k.o.d]

The addition of aquarium salt was used as a 'tonic' as it altered the osmotic balance of the fish in the water and thus made respiration easier.
If you have true freshwater fish (not brackish) and they are not unwell, the addition of 'tonic' salt in an unneccessary expense.

 

[Corleone]

Aquarium salt also alters the toxciticy of nitrite and nitrate. It was very popular in the mid/late 20th century with poor understanding of the nitrogen cycle making a lot of noise about "old water" and general fear of water changes. It stresses fish that don't need it, but when you run on no water changes for months or years, it becomes the smaller of two stresses.

The stuff sold as "aquarium salt" also isn't ideal for brackish fish, either, though it will work with some of them and is suitable in the short term for many others. It has different ionic content than marine salt.

 

[OldMan47]

Salt is very easy to characterize. the tonic effect is simply misinformation. the effect of reducing nitrite toxicity is very real. Unfortunately the amount of salt needed to reduce nitrite toxicity is so small it would be difficult to measure and dose, we are talking no more than a very few ppm here. A much more effective way of dealing with nitrites is to remove them with a simple water change. It not only reduces but can eliminate any threat from nitrites.
A small pinch of salt can be useful in a shipping bag to offset the build of nitrites while a shipment is happening. I suspect that few of us here are shipping fish over several days where a pinch of salt would help the fish being shipped. For fish in a tank, you are better off removing the nitrites than trying to slightly reduce its toxicity by using a pinch of salt.