Slow Escalation of Salinity?

[Richie_ELP]

I'm in class for an hour and the conversation shifts from diffusion to breaking wind. Only on MFK.

 

[Lupin]

i think all that needed to be said pertaining to the topic has been said.
not smart to try convert a fw fish to sw.

It doesn't apply in general. A few freshwater species actually can manage conversion to saltwater environment such as guppies and mollies especially if the process is gradual however anything else that lacks the proper osmoregulatory process to cope with the increased electrolytes may likely weaken and eventually die in the process. Of course, we have to exempt the unique cases of those that migrate to estuarines and even fresh water to breed wherein the fry eventually migrate where their parents originated.

In this case, the answer is no. You should NOT attempt to convert the fish in question. It'll do it more harm than help in fact.

 

[PostalPenguin]

Even over several years it would be impossible. Here is why:

Enzymes in the fish have adapted to fresh water. Now you can expose fish over a few days to increased salinity(for ich treatment). This is safe because the salinity is still not enough to completely disrupt cellular processes and the fish can extract the salt from the water and excrete it out of their body. However, if you increase the salt high enough, you will overwhelm the ability of the fish to correct this while also preventing the activity of the enzymes.

Now you may think that over a few years you would be able to adapt the fish. This would still not work. Eventually the salt would reach a point where enzymes started shutting down and the fish's cellular machinery would fail and the fish would die. Sure you may be able to get up to a pretty high salt level but eventually certain enzymes would simply not work well enough to keep the fish healthy.

Simply put, the fish is stuck with the genes it has and these do not code for salt water active proteins.

So if you wanted to make the fish tolerate salt you could either breed the fish with successive generations in saltier and saltier water but this would take years if not decades if ever. Another option would be to expose the fish to mutagens that damaged its DNA while again breeding the fish in increasing salinity. The mutations may give the fish the ability to grow in salt with each successive generation getting a few new mutations that could give salt active forms especially when selective pressure is selecting for higher salt tolerance. But this would likely also lead to cancer, altered coloration, reduced fitness and a bunch of other problems.

Certain fish that can be adapted to fresh and salt likely have evolved the ability due to their natural habitat changing from fresh to salt. Their DNA likely codes for proteins that function in fresh and another set that functions in salt.

 

[Dark Jester]

^^ Well said.

 

[MonsterMinis]

Even over several years it would be impossible. Here is why:

Enzymes in the fish have adapted to fresh water. Now you can expose fish over a few days to increased salinity(for ich treatment). This is safe because the salinity is still not enough to completely disrupt cellular processes and the fish can extract the salt from the water and excrete it out of their body. However, if you increase the salt high enough, you will overwhelm the ability of the fish to correct this while also preventing the activity of the enzymes.

Now you may think that over a few years you would be able to adapt the fish. This would still not work. Eventually the salt would reach a point where enzymes started shutting down and the fish's cellular machinery would fail and the fish would die. Sure you may be able to get up to a pretty high salt level but eventually certain enzymes would simply not work well enough to keep the fish healthy.

Simply put, the fish is stuck with the genes it has and these do not code for salt water active proteins.

So if you wanted to make the fish tolerate salt you could either breed the fish with successive generations in saltier and saltier water but this would take years if not decades if ever. Another option would be to expose the fish to mutagens that damaged its DNA while again breeding the fish in increasing salinity. The mutations may give the fish the ability to grow in salt with each successive generation getting a few new mutations that could give salt active forms especially when selective pressure is selecting for higher salt tolerance. But this would likely also lead to cancer, altered coloration, reduced fitness and a bunch of other problems.

Certain fish that can be adapted to fresh and salt likely have evolved the ability due to their natural habitat changing from fresh to salt. Their DNA likely codes for proteins that function in fresh and another set that functions in salt.

I think.. thats the explination as to why you don't trap yourself into a small box and fart for 2 years... on another note.. OP you could have done a search.. and come up with more then a few threads reguarding this topic and giveing you the answers you where looking for.

 

[Moloch]

So...if I were so inclined I might set out on a life-long project of breeding a particular fish closer & closer to a FW to SW conversion?

The opposite seems a little more enticing...SW to FW.





(*disclaimer, I would never actually do this. Its completely mad-scientist)

 

[Big_Z]

Try it with convicts it would take what 5 days to go through 100 generations of them Forcing evolution

 

[12 Volt Man]

the histology of the fish prevents this from happening.

the osmoregulation is different too.

many brackish water fish (like Scats for example) have cells in their gills called chloride cells that excrete salt.

a firemouth for example, doesn't have these cells. its a lost cause.

 

[theunytedone]

im NOT doubting the plausibility of the process being described, just remarking upon how it should NOT be done...it doesnt seem healthy for the fish, i dont see what would spur the urge to TRY and convert it...nor do i see benefits of HAVING a now-saltwater fish after all that "hard conversion work"

sure there are also cases of saltwater organisms making their way to deltas and thus becoming brackish...and thus maybe even full-freshwater.

i dont even know what the argument is.

just leave the fish you got in the kind of water it came with lol. i dont see anything difficult about that.

 

[Dark Jester]

No arguments related to the thread topic. OP was just asking if it was possible. Think everyone agrees even trying would be torture for the fish.

I'll get to work on your pygmy elephant Ar0wan. Now do you want that to be acclimated to salt or fresh water?