Response to article Salt in the Freshwater Aquarium
 

Hello Friends,
In the article about salt it is implied the use of any salt is undesirable with tragic consequences. The issue for me is the concentration and not salt. We all know too much of a good thing is not necessary a good experience. Perhaps less is best when it comes to freshwater aquariums and sodium chloride.

As pointed out “adding salt to a freshwater aquarium on a regular basis will, at best, do nothing of any value at all. But at worst, it will stress salt-intolerant fish, making them more vulnerable to disease and less likely to live a healthy and normal lifespan”. Yet the article goes on the point out “salt is a mineral that is composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of ionic salts. It is essential for animal life in small quantities” (I assume this includes freshwater fish). Where do freshwater fish get the apparent necessity of ionic salts if not from the salt in the water.

If ionic salts are not present would osmoregulation deplete this essential necessity from the fish’s body creating even more stress and imbalance of the fish’s normal body functions? The metaphoric image of stepping on the gas certainly would apply to this situation,
As for the “increased energy output is wearing down the fish, and the fish is not able to expend this crucial energy on other important functions. The growth rate is affected, a shorter lifespan will usually result, and there will be increased risk of various health problems along the way.” Seems to me there is something missing in this paradigm I take it fish’s ability replenish energy, access of oxygen, ect. is forever impaired.

The concept of total dissolved solids is interesting and should be considered at all times. Would ammonia, nitrites and nitrates be considered as part of the TDS and also affect the osmoregulation process? Lets look at the uptake of nitrates. Through the osmoregulation nitrates in the water seek to balance the concentration of nitrates in the water column with nitrate concentration in the fish’s body. When the fish’s body concentration of nitrates becomes excessive they reduce the ability of blood to carry oxygen resulting in the death of the fish.
I am not sure but I think salt does not dissolve in water but is held in liquid suspension a lot like sugar is. When in this state of liquid suspension the neutral charged chloride ion by osmoregulation can be uptaken by the fish and when this neutral charged chloride ion is in the fish’s cells it prevents the uptake of nitrates and reduces the potential for nitrate sickness.

I am not claiming any opinion about the use of salt in a freshwater aquarium, nor am I disagreeing with concept presented in Salt in the Freshwater Aquarium. I am presenting an alternative view.

To some the glass is half full to others it’s half empty.

pop

I am not a biologist, and thus can't say exactly the amount of salt that may be required by a fish. I accept the view of the scientific community that salt is essential to life, but I also accept their view that soft water fish don't need it added.

If we look at the water in natural habitats in tropical areas where soft water fish have evolved and live, we find it so low it is often undetectable. I have never added any salt to my tanks, and the water out of my tap is so soft the GH is around 7ppm, less than one degree. Yet my soft water fish have lived their expected lifespans and been healthy, and many have spawned regularly. Obviously there is no need to be adding it, especially when one considers the obvious risks. Avoiding stress is paramount to healthy fish.

Byron.

yes, technically anything that passes through a membrane filter with a pore size of two micrometers is considered a component of TDS

but, osmoregulation is about balancing water not ions, water passes passively into and out of organisms due to a concentration gradient, it is the active transport of ions that controls the gain or loss of water by altering internal ionic concentration to lessen or increase the gradient

NaCl absolutely willl dissociate in water and result in positively charged (cation) Na and negatively charged (anion) Cl, some will remain as NaCl; ions by definition carry a charge that results from gaining or losing one or more electrons