Found this on Facebook and have heard it from some knowledgeable fish keepers.
The most common incorrectly suggested treatment for Ich is HIGH TEMP and SALT.... Here is why its NOT.
Salt Sodium Chloride. Aka Table salt, Rock salt, Kosher salt, Regular salt, Aquarium Salt. It is a chemical. Many think its natural. And while it comes from mother earth. It is still listed as a chemical. Much like many other chemicals Like Hydrogen peroxide. Nothing more then H20 =Water and O2 oxygen. The thing to remember about Sodium Chloride is that fresh water fish spend their entire life burning much energy trying to remove fluid and Sodium from their bodies. This is the function of osmosis. By adding more sodium chloride you have now made the fish work even harder to keep osmotic balance. This can cause issues with higher salt exposure that decreases the fishes Immune system. It can cause issues with cortisols being out of balance. also note that Adding salt to the water ALSO decreases dissolved O2 levels as it becomes a dissolved solid in the water displacing the O2 and this is why Salt water has less dissolved O2 then Fresh water. Salt was a cure thought up by the aquaculture industry for fish farming for food. Where the longevity of the fishes life only matters enough to get them fat to harvest. Not like we keep fish in any way. heat as a cure us just not in my book of treatment and I can explain why. Its fairly simple. If you understand the Biology of the Ich parasite and the biology of fish and how they get it, how they react to it and the issues it brings then you will see heat isnt the best over all treatment. .. So First lets understand Ich. How does it Kill. It kills by basically suffocating the fish. How does it do this? It does this by first attacking and covering the gill tissues with its ich parasites. Doing so covers valuable space/area for the fish to take in O2. This causes the first reduction in O2 to the fishes body. next step is the parasites are feeding on the Gill tissues and the fluids in the fishes body. Due to this it is pulling valuable fluids of blood that carry the O2 to the rest of the fish. BUT now cant as it is being sucked away from the fish. So you now have double impact on the fish Reduced area for O2 intake and now the intake the fish is getting is being sucked away. Ok.. So now the parasites are all over the body doing this fluid and tissue damage and causing heavy amounts of osmotic loss and misfunction. The fish has a biological response to protect itself from such. It thickens the outer membrane of the gill tissue to try and shed the ich parasite. Unfortunately the ich have dug in to hard. Now we have a new impact on the fishes intake of O2. By thickening the walls/membrane of the gill tissues it will reduce O2 levels even further. And eventually this membrane will swell and rupture and separate from the over layer causing massive amounts of O2 loss and the actual loss of fluids at a higher rate causing the fish to now also suffer even heavier from osmotic failure and will for sure suffocate. NOW lets add increasing temps in the water. There are lots of factors that effect the amount of dissolved o2 levels in water. Such as Volume and velocity of water flowing in the water, the type and number of organisms in the water and all organisms use O2 for the most part including many bacteria and other things. Altitude, as atmospheric pressures are different all over the world and these have great effects on how much O2 can actually even break into the water. Higher altitudes have lower O2 levels The levels of O2 at sea level will be saturated the most. Dissolved or suspended solids. If your water is hard vs Soft (also note that Adding salt to the water ALSO decreases dissolved O2 levels as it becomes a dissolved solid in the water displacing the O2 and this is why Salt water has less dissolved O2 then Fresh water) So minerals and various different solids can have an effect on the dissolved O2. Amount of nutrients in the water can also make a difference. Organic Wastes and dissolved organics will reduce the amounts of O2 levels in your water. Higher water Nitrate contents or Ammonia and or Nitrite. Even things such as algae blooms. So all these things will effect how much dissolved O2 levels are in the water. Now combine this with the issues I explained above how fish fight off ich and the issues there and how the ich attach fish and what that causes. It makes you think and see that Oxygen is harder to come by. Now lets raise the temperatures up. Realize that at 80 degrees that water holds ( if all conditions are at the best see above things that effect it) roughly at 80 degrees F (26 C) water holds about 10ppm at given conditions. Now heat the water up to 86 F (30 C) and your dropping the dissolved O2 levels down to around 6 to 5ppm of dissolved O2 levels. (these can be figured by using formulas such as Solubility and Henrys law to figure out Deaeration values and it can get complex with adding in the factors I mentioned above for water parameters) So as you can see, Increasing temperatures is not the best answer. Yes The ich parasites metabolism speeds up. It makes it reproduce more and more and it also makes its life cycle accelerate. But again this can have a double impact on the fish due to more parasites being born. There are and have been identified strains of ich resistant to salt and resistant to heat at temps even as high as 92 degrees. Then comes the additional factors to weigh in on. Secondary infections. The Ich may not kill the fish in many cases but secondary infections of various bacteria that thrive in high water conditions and fish with heavily weakened immune systems. This is exactly why I never recommend raising temps. Its in the science and not just a repetitive thing thats been tossed around. Using a proper treatment for this parasite is most beneficial and most will not destroy your beneficial bacteria and if you treat correctly with products like Quinine sulfate or Chlorenque. These two above effect ich in all stages. Products that contain zinc free Malachite green and formalin base work very well and are easy on sensitive fish if dosed half dose same. Then at the same time you can use a treatment of triple sulfa. It acts as a buffer for many fish for the compounds in the other treatments listed and it also helps protect against secondary infections. These are my recommendations. The ones I listed above, some can be used effectively in half doses even and work for sensitive fish species. Can heat and or salt work? Yea. But realize all of the risks and potential issues. Much has changed and advanced over the years.