lower salinity in fish only tanks ??

[cracker]

I read here and there that lower salinity is best for fish only tanks. I've seen this mentioned many times over the years. For instance, I was looking at the specs on a new bag of salt. Ya know, at this lower salinity ( fish only) levels will be in that range. At that higher salinity (corals) it will be in this range.
I have always kept my salinity at 1.025/26. If so , what are the advantages to running lower salt levels in fish only tanks ? Or have I just been reading too much ?

 

[Antics]

I've seen people with success anywhere between 1.019 and 1.027 long term in FOWLR. I ran a FOWLR for a year that was quite overstocked at 1.026 with zero issues with my fish. I'm not sure if there is any real/tangible benefit to lowering the salinity specifically for fish only.

 

[cracker]

That's what I'm looking for, real benefits to lower sal. Just a lot of opinions. Algae doesn't like it but neither do snails, fish breath easier etc. Any solid reasons out there? I will keep my salinity at .25/.26 anyway just curious.

 

[Crashjack]

I believe the lower salinity myth was created to benefit wholesalers not fish. The claim is that lower salinity eases/slows osmoregulation. I found nothing but the contrary when searching for some scientific proof. What I found was that most fish optomize osmoregulation at the salinity from which they come. I think it is also common sense. According to NOAA, salinities in the world's reefs vary from around 1.024 s.g. to around 1.032 s.g. It makes sense that fish would adapt to the conditions in which they've lived forever and that altering salinity to something lower or higher wouldn't miraculously make a fish healthier.

 

[Waters]

All of the LFS around me run their fish only tanks at a lower salinity to keep parasites at bay.

 

[Newb73]

That's what I'm looking for, real benefits to lower sal. Just a lot of opinions. Algae doesn't like it but neither do snails, fish breath easier etc. Any solid reasons out there? I will keep my salinity at .25/.26 anyway just curious.

Dissolved oxygen can be higher with lower salinity....and its cheaper for the lfs. Temperature and atmospherics pressure are also variables.

My tank is heavily stocked and i run my temps 79 to 81 so ive run my tank closer to 33 lately.

If you lived in the mountains it would be advised to lower my temp to 78 to 79 as well and probably stock lighter.

This really only becomes an issue if there is an extended ppwer outage.

In the summer i run 1 degree or so lower.

 

[theMeat]

Lower salinity makes it harder for most parasites to thrive, and lowers stress for fish. This is not a myth, or an angle to save money on salt for lfs. It’s tried and true proven.
You can safely drop the salinity level right quick, but should raise it slowly. Like no more than 2 points per day to be safe. So when you buy a fish from lfs that runs low salinity, be aware of what their level is compared to your own.

 

[Crashjack]

Lower salinity makes it harder for most parasites to thrive, and lowers stress for fish. This is not a myth, or an angle to save money on salt for lfs. It’s tried and true proven.
You can safely drop the salinity level right quick, but should raise it slowly. Like no more than 2 points per day to be safe. So when you buy a fish from lfs that runs low salinity, be aware of what their level is compared to your own.

Where is the scientific proof? I searched and read through a few published papers, and though these studies were mostly oriented around commercially raised fish, they cited that the best osmoregulation for saltwater fish in general, typically occurred at the salinity of a fish's natural environment. It is known that parasites can thrive at salinities above hyposalinity and even a few strains can supposedly exist at hypo levels. True, the lower salinity you go, it is likely that more and more parasite strains are affected as it is it is below what they encounter in nature. However, does anybody really know how much impact?

My point is, if a fish that literally bathes in its environment and has evolved and adapted to that environment, there is going to have to be some serious scientific proof that fish actually fair better long term in a different environment, before I'll jump on the lower salinity bandwagon.

 

[Newb73]

Where is the scientific proof? I searched and read through a few published papers, and though these studies were mostly oriented around commercially raised fish, they cited that the best osmoregulation for saltwater fish in general, typically occurred at the salinity of a fish's natural environment. It is known that parasites can thrive at salinities above hyposalinity and even a few strains can supposedly exist at hypo levels. True, the lower salinity you go, it is likely that more and more parasite strains are affected as it is it is below what they encounter in nature. However, does anybody really know how much impact?

My point is, if a fish that literally bathes in its environment and has evolved and adapted to that environment, there is going to have to be some serious scientific proof that fish actually fair better long term in a different environment, before I'll jump on the lower salinity bandwagon.

Conjecture: In instances where the disease impacts the gills, fish can oxygenate better in a lower salinity in a disease state.

The lower salinity may also disrupt microorganisms processes which are mediated via osmosis related transports and nutrient/gas/energy exchange.

Be that as it may, hyposmolarity also effects fishes renal function, eventually leading to a shortened life span...for similiar reasons that it may ****** the spread of microorganisms.

Edit...above i used r e t a r d in its non pejorative form, it got edited.

 

[theMeat]

Not going to argue with you. Or take the time to find “scientific proof” . Have been in the hobby for decades and only trying to share my experience. Have witnessed what i’v shared many times over, again and again. That’s all the proof I need.
I’m not suggesting hypo for long term. But on the lower end of things, and lower than what need be for coral or inverts in a fish only is fine.

 

[Newb73]

Not going to argue with you. Or take the time to find “scientific proof” . Have been in the hobby for decades and only trying to share my experience. Have witnessed what i’v shared many times over, again and again. That’s all the proof I need.
I’m not suggesting hypo for long term. But on the lower end of things, and lower than what need be for coral or inverts in a fish only is fine.

I don't have experimental proof but i did submit the theoretical evidence for ya...

 

[skiergd011013]

I work at an aquarium and we keep fish only tanks between 1.017 to 1.020

 

[Crashjack]

Not going to argue with you. Or take the time to find “scientific proof” . Have been in the hobby for decades and only trying to share my experience. Have witnessed what i’v shared many times over, again and again. That’s all the proof I need.
I’m not suggesting hypo for long term. But on the lower end of things, and lower than what need be for coral or inverts in a fish only is fine.

Definitely not my intention to argue for the sake of arguing, just stating my opinion based on my research, experience, and logic (this is my second stint in the hobby). I also realize that lower salinity water holds more oxygen as does lower temperature water. However, assuming a system isn't deprived of oxygen, who is to say that elevated oxygen levels are better for fish... and whether the additional oxygen is best created by reducing salinity, reducing temperature, or by reducing both, without doing some real research?

 

[Newb73]

Definitely not my intention to argue for the sake of arguing, just stating my opinion based on my research, experience, and logic (this is my second stint in the hobby). I also realize that lower salinity water holds more oxygen as does lower temperature water. However, assuming a system isn't deprived of oxygen, who is to say that elevated oxygen levels are better for fish... and whether the additional oxygen is best created by reducing salinity, reducing temperature, or by reducing both, without doing some real research?

Neither are needed as long as the water is fully oxygenated any way.

Could be useful if the fish is in distress though....or in the event the power goes having higher starting point might be useful.

 

[theMeat]

Newb73 makes a good point. Plus, fish have blood, inverts, which include parasites, do not. That’s why fish are much better able to deal with lower salt. Can inverts tolerate some lowering, sure. Some better than others, sure. It’s not 100% anything. Just something that helps, is easy to do, and is perfectly fine in fowlr

 

[Crashjack]

My issue is simply that I've seen no evidence that lower salinity is "better" for fish, unless it is part of an active treatment regimen (hyposalinity). I don't know if lower salinity is any "worse" for fish, but it isn't natural so I personally would stay away from it. The problem I have is online vendors shipping fish at low salinities, creating more work for me to bring my QT's salinity up to my reef,

 

[theMeat]

My issue is simply that I've seen no evidence that lower salinity is "better" for fish, unless it is part of an active treatment regimen (hyposalinity). I don't know if lower salinity is any "worse" for fish, but it isn't natural so I personally would stay away from it. The problem I have is online vendors shipping fish at low salinities, creating more work for me to bring my QT's salinity up to my reef,

The proof is in the pudding

 

[Crashjack]

The proof is in the pudding

If by proof you mean online vendors shipping at lower salinities, then Divers Den doesn't know what they are doing as they typically ship at 1.024-1.025 s.g. What I have witnessed is, the less a particular fish costs, the lower the salinity you can expect.

 

[Brew12]

Unfortunately, I don't have access to this article any longer but scientific studies have been done showing reduces parasitic reproduction at lower salinities.
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2761.1979.tb00146.x/full

 

[theMeat]

No the proof is in the pudding because I’v done it, countless times, and it works. That’s why the industry and hobbyists alike widely use this practice. Or maybe everyone does it and continues to because it doesn’t work. And it’s some big cover up to save a few pennies on salt.