You cannot turn any random fresh water fish into a salt water fish. You cannot turn a salt water fish into a fresh water fish. Each species of fish has a specific range of environmental variables that it can survive within. While a fish may be used to one set of extremes of those variables and you can accustom said fish to the other end of the extremes of said variables by adjusting its environment over time, you cannot acclimatize a fish to living in an environment whose level of saltiness -- and other chemicals, temperature, variables, etc... -- is outside of the range for which that particular species can survive.
Fresh water fish and salt water fish have evolved to survive in the salinity -- the level of saltiness -- of their native environments. Salt quantity isn't the only difference between salt and fresh water. There are many other variables, ranging from other chemicals to various organisms. These would have to be adjusted, too.
There are a handful of species that can go between fresh and salt water, but most of those require being in one or the other (or both) for some period of time throughout their life cycles.
http://www.freepatentsonline.com/6016770.html
This patent covers a process for acclimating saltwater fish to fresh or brackish water. It explicitly calls out that not all species are compatible with such a change in their environment. The subject of fresh to saltwater conversion or acclimatization is completely avoided. (Coincidentally, the patent has expired due to non-payment).
These articles and further research shows no evidence that anything but very specific species are capable of moving from freshwater to saltwater. Of those species, I could find none that move from freshwater to saltwater permanently and, certainly, no evidence of a acclimatization regimen that might enable a random freshwater fish to live permanently in a saltwater environment.
The red thing mostly has to go along with informing the younger ones of mfk. They look up to red, as i know i once did for everything. I got a little more knowledge and still follow mostly what they say. Most can see this is just stupid, but some can't. Also some people just come in here to instigate, and they should receive an infraction