convert salt to fresh?

[fishdude92]

is it possible to convert saltwater fish to freshwater fish over a long peroid of time?
i just read an article on freshwater stingrays and how they were isolated from the ocean and had to evolve to live in freshwater

http://www.aquarticles.com/articles/breeding/Webber_David_Freshwater_Stingrays.html
"It is thought that all of these Amazon rays are most closely related to Pacific Marine rays. Their isolation would have occurred when the Andes Mountains rapidly rose up about 15 million years ago, blocking the Westward flow of the river as it then was and forcing it to flow east all the way to the Atlantic, trapping many rays in the new system. This isolation and the Amazon’s tropical climate and seasonal massive changes in water levels created ideal circumstances and great pressure for evolutionary changes, as represented by the huge variety of stingrays found in just the one system. Even individual species that are found along the whole river, such as Motoros and Histrix, are polymorphic, each exhibiting their own wide range of colors and patterns as habitat and available diet change subtly between regions."

[Sweetheart]

I don't think it's possible

[trashion]

Uh, evolution takes place over millions of years, through thousands of generations of a species. So maybe in a million years, a specie of clownfish would become adapted to freshwater, but you can't take a fish and condition it over time to live in FW.

[fishdude92]

has anybody tried it yet? any scientist?

[fishdude92]

i mean if there is glowing fish and we have reached mars and stuff, im pretty sure it is possibly, its just that nobody tried

[Andrew7769]

the point being? there are already species that can go from one environment to the other like mollys and stuff i don't see a purpose really.

[Ace25]

Yes, it can be done. I have done it myself to cycle tanks. You can add freshwater mollies to a tank and over a months time slowly raise the salinity to ocean levels. This can be done in reverse as well. I wouldn't try it with any other fish though.

http://www.peteducation.com/category_summary.cfm?cls=16&cat=1958

Mollies are members of the Poeciliidae family and are widely distributed from the southern United States to South America. Mollies are very versatile fish having the unique ability to live in both freshwater and saltwater if acclimated slowly. Some saltwater aquarists use mollies to establish a new marine aquarium. Mollies are tolerant of a variety of water conditions, but prefer some aquarium salt in the water for optimum health. Ideally at least a tablespoon of aquarium salt per gallon minimum is recommended.

[equus_peduus]

I believe mollies are brackish, so they can adapt to either.

When a mountain rises "rapidly," I think that still takes thousands of years. Probably there was a transition period of brackish water in those areas as well.

The problem is the way freshwater and saltwater fish are adapted to deal with water. Saltwater fish drink water, keep the water, and pump out the salt. Freshwater fish drink water, keep any salt, and pee the water out. So while they theoretically could adapt to the opposite conditions, I think that it would be difficult to do in most cases. You'd need a species, like the molly, that already has some ability to do either.

[Lupin]

Damsels are one of the few that can be converted to freshwater if salinity level is lowered gradually but this is not advisable as they will be subjected to physical harm as their osmoregulatory system will not function well enough compared to higher salinity level in the long run thus unable to live for a long time in comparison to those kept in saltwater. Mollies are one of the few that can indeed be done on both ends. Guppies are another but IMO for long lifespans, it is not advisable to subject them to these processes.

[fishboy93256]

it can be done i made a fresh water fish in to salt water it took me a yea thou i had to raze th slinitey and ph slow ley