I want to talk about these points one by one.
Salt helps by lowering the difference in osmotic pressure between the fish and the water
This is a fact from thermodynamics analysis. Simply put, the concentration of minerals (a real catch-all term for all the salts, sodium, potassium, magnesium, calcium, etc) between the fish's internal fluids and the outside water will be brought closer together, to the osmotic pressure difference will be lowered.
thus reducing stress and assisting by allowing more energy to the healing process.
This is the statement that really bothers me. The fish have adapted and lived their entire life with this pressure difference. If I took away 25% of the earth's pressure from you, I guarantee that you would not feel relieved of its stress. You would in fact most likely feel quite disorientated. For example, how many people suffer from altitude sickness when they go from sea level to Denver for instance? That is only a 10% or so drop in pressure (and yes, I know that at least some of that is a change in the amount of oxygen, too. But a classic experiment reported in 1991 by Maxime et al. in
Journal of Comparative Physiology B took trout from freshwater to saltwater. After 1 hour, the fish was respiring 55% more in saltwater than fresh, though after 24 hours it settled down to 20-30%. Measurements showed that after 24h, plenty of time for adaptation, the gill oxygen transfer was only 88% in salt water what it was in fresh. Therefore, the comparison between the thinner air in Denver and the thinner ability of fish to take oxygen from salt water is at least in the ballpark).
Not only has the fish in question lived its entire life with the osmotic pressure, but its species has for many hundreds of thousands of years. Evolutionarily, if salty water was so much less stressful, why have so many fish remained primary freshwater fishes? If salt relieved so much stress, wouldn't every species have eventually gone out the ocean?
In short, I am just not buying the less-stress argument.
It also creates a 'thicker' slime coat which will help repair
I also question this justification for salt, since it seems directly in conflict with your previous statement. If you want 'more energy to the healing process' why would you want to have to expend more energy to thicken your slime coat? The slime coat has to be refreshed periodically, and if it is thicker, you have to replenish more of it, hence you have to expend more energy to do so. So, if anything, energetically, this is a strike against salt.
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Now, all that said, to address the original poster, adding salt to freshwater fish is a very tricky subject. I would recommend a read through of a very recent thread
http
/www.fishforums.net/index.php?showtopic=155280&hl=
There were people on that thread for both sides, but among the main points I'd like to reinforce is the difference between primary and secondary freshwater fish. Primary freshwater fish have an evolutionary history that has always remained in freshwater, like tetras and carp (of which your RTBS is a member). Consequently, they never developed the internal mechanisms for dealing with higher mineral content. The secondary fishes have in the past been saltwater fishes, though now reside in freshwater. Consequently, they have at least a rudimentary mechanism to take care of higher mineral contents, a sort of genetic memory so to speak. It is certainly not as proficient as a current day saltwater fish, but they still have some of the ability to handle salt. (Sort of like how people still have a tailbone. We don't use it anymore, but it is part of our genetic history.) Now, the tough thing is that these are all relative. There are primary freshwater species that do indeed handle salt better than some secondary freshwater species. However, as a group, primary freshwater species as far poorer at handling salt.
Frankly, I would recommend doing frequent water changes and feeding a higher protein food over salt to help speed up the healing process. Most fish are much perkier after a water change, and the higher protein will help the tissue formation process. Also, from your other thread, I know you have some non-expired Melafix now, and some people have had good success with that.
