Aquaworld Aquarium - Article - Adding Salt to a Freshwater Aquarium

Some Suggested Salt Sources for when salt is used in a freshwater aquarium:
Photo provided by Flickr
The article also makes mention of the inability to judge any consequences of using salt on freshwater fish. To say you use it and it has no side effects is like saying you smoke but you don't have cancer. How do you know you won't have it ten or twenty years from now? And similarly, how do you know the salt did not have some internal effect on the fish that may cause problems later? You don't, and neither do I. My approach is not to inflict the fish in my aquaria with something that is not in their natural habitat unless it is absolutely essential. That seems the safest route to follow, and the authorities cited in the linked article, as with those I have previously read, are not in disagreement.
Non-iodized table salt is generally recommended for use in freshwater aquariums.
Photo provided by Flickr
The Bad:
The problem with salt is that it is often suggested to be added all the time, with every water change. These are freshwater fish, not brackish or marine. They do not need salt added to their water. They have adapted to freshwater chemistry, that is what their kidneys can handle. Adding salt all the time, especially at the dosing suggested by the companies selling salt who want you to buy a lot of it, is not food for the long term health of the fish. Lake Tanganyika is one of the hardest, most alkaline bodies of freshwater on the planet. Seachem's Cichlid Lake Salt has a recommended dose of 1/2 tablespoon per ten gallons. The usual recommendation for aquarium salt to be added to freshwater aquariums all the time is one tablespoon per five gallons. That is four times as high as one of the hardest and most extreme bodies of freshwater on the planet. Subjecting all freshwater fish to this salinity, especially soft water fish, is going to cause harm long term. They simply are not adapted to handling such a salinity, their physiology is not able to handle it safely long term. There’s no need to use any salt. Salt should only be used occasional in freshwater aquariums and usually only to treat for illness.
Photo provided by FlickrCountless generations of mollies have been bred and raised in freshwater aquariums with no salt. I've done the same too. HTH.
Photo provided by FlickrAlgone is an versatile aquarium supplement that works gently and is perfect for use in delicate saltwater and freshwater environments.
Photo provided by Flickr
Freshwater, as in rivers and lakes, does not have appreciable salt content in nature. Most of the plants that we see in an aquarium come from such habitats. As these plants have evolved in freshwater, appreciable amount of salt and/or salty water must be a foreign condition to which a plant has to adapt if it can. Let us examine what salt would cause.
I have come across the comments of several aquarists saying that they just cannot grow even the easiest of aquarium plant. When I read such comments it comes into my mind that ‘1 teaspoon per 10 gallon’ salt addition advice. Salt does not evaporate from the aquarium once it is added. More salt with water changes and topping up, if unregulated will simply increase the salt content to a level where it shall make it hard for freshwater plants to survive.We know that higher amount of soluble solid content increases the internal pressure in the water, demonstration of osmosis in physics have shown how water with lesser amount of solids in solution tends to equalize by escaping through a semi-permeable membrane into a more concentrated solution on the other side. The outer skin of an aquatic plant is semi-permeable. So when we add salt to the freshwater aquarium in any appreciable quantity, there is a chance that a plant will loose its internal water to its surrounding. In other words the plant will wilt.In the U.S. since the 1990s it's been a common practice to add salt to freshwater aquariums to prevent some diseases and balance osmotic pressure. it's been added for so many years that some freshwater fish get sick and die without it. Do you add salt?So next time those of you who find it hard to keep plants in your aquariums, try your hand at planted freshwater aquarium, go lightly with salt, and see how easy it is to grow plants. A sand and gravel substrate to anchor the plant, and a little light about 1.5 to 2 watts per gallon and you will enjoy the beauty of a planted aquarium and your fish too will thank you for it. The most important use of salt is for medicating freshwater fish for some types of ectoparasites (parasites on the outside of the fish). Some of the common parasites that are know to be killed by salt are ich (),, Anchorworms (). To kill these parasites with salt, you need to add a lot of salt, about 1½ cups of salt per 10 gallons (38 l) to the aquarium, not just a teaspoon per 10 gallons. The "Specific Gravity" measured with a standard marine aquarium hydrometer should be between 1.005 and 1.009 or 7 to 13 ppt. If treating for Anchorworms closer to 1.009 would be best. This level of salt needs to be maintained for at least 3 weeks. Not all freshwater fish can tolerate this much salt. Generally Central American cichlids and livebearers, African rift lake cichlids, and Koi can tolerate this much salt. Saltwater dips are also common for eradicating some external parasites. A saltwater dip with a specific gravity of 1.009 to 1.023 for 30 minutes to 2 hours is know to kill (skin flukes). When ever treating freshwater fish with salt, you should monitor the fish closely for excessive stress, and return the fish to freshwater when necessary. In many cases, treating external parasites with other types of medication may be safer for the species of fish you are trying to cure.