fish surviving with the salinity at 1.035

[Strictly Marine]

I had a customer come in today trying to get a new fish. She brought a sample water so I did the test for her. The 1st thing I did was check the salinity and it was at 1.035 I was shocked to say the least. She said that the fish acted weird but other wise ok. I advised her to bring the salinity down to 1.025 over a period of at least 6 hours. I wasn't sure whether the sudden change whould be more harmful then the high salinity.
Have any of you ever had something like this happen. Didn't think fish can survive at that high salinity.
So I loaned her one of my hydrometers, just hope she brings it back.

 

[wseaton]

High water density makes it tougher for fish to breath for the worst part and helps parasites such as ick. Thats' why FO tanks can't be kept at salinity of much less than .020 and the fish do fine, if not better.

A rapid change of any water parameter isn't good for any marine life, but it's much easier for fish to deal with a drop in salinity vs the other way around. It's large polyps, mushrooms, and anemone's that will have a very hard time with a rapid salinity drop.

 

[two11devan]

I think bringing the salinity down that much over 6hrs is too quick.....i would think it should be done over several weeks with water changes JMO...somone correct me if im wrong

 

[reefrunner69]

I would bring it down over the course of a week, if there are any mobile inverts in the tank....that large a change over 6 hours could be deadly...the fish shouldhandle it OK, but IMO it's still a little too fast.

FWIW, according to Dr Ron's article on temps and salinities...fish can cope with hypersalinity much better than hyposalinity.

 

[Guest]

I agree with Kevin. Take your time dropping the salinity..


Wseaton, could you elaborate a bit with the below statement?

Thats' why FO tanks can't be kept at salinity of much less than .020 and the fish do fine, if not better.

 

[Terry B]

It sure would be easy to debate that fish do better in hypersaline water than in hyposaline. Hyposaline conditions are much better for fish than hypersaline conditions. I can back up my opinion with numerous scientific references.
Terry B

 

[Sneaker]

I had a customer come in today trying to get a new fish. She brought a sample water so I did the test for her. The 1st thing I did was check the salinity and it was at 1.035 I was shocked to say the least. She said that the fish acted weird but other wise ok. I advised her to bring the salinity down to 1.025 over a period of at least 6 hours. I wasn't sure whether the sudden change whould be more harmful then the high salinity.
Have any of you ever had something like this happen. Didn't think fish can survive at that high salinity.
So I loaned her one of my hydrometers, just hope she brings it back.

Sounds like you should of sold her the hydrometer, I think she needs it...

 

[reefrunner69]

I can back up my opinion with numerous scientific references.

Please do, I think either condition long term would be detrimental to the fishes kidneys, but my only reference is Dr Ron's article on Salinities and temps.

What are Natural Reef Salinities and Temperatures…Really…
and Does It Matter?[/url]]The lower salinity limit for most reef animals is about 30 ppt, which is normally found in estuaries or around river mouths, or periodically in some lagoons after substantial rainfall. Coral reefs are generally located in areas that have salinities in the range of 35 to 38 ppt, although most of the Red Sea and Persian Gulf exceed 40 ppt (see Figure 2) (Sverdrup et al. 1942). The upper limit it seems is about 42 ppt, which is reached in some hypersaline lagoons. Most organisms, even osmoconformers, can survive for brief periods in salinities well outside their normal ranges. But, if maintained for a longer period outside of that range they will be stressed and eventually will die. Higher salinity is more tolerable to these animals than is lower salinity, and adult animals are more able to withstand the extremes than are the juveniles or larvae.

What are Natural Reef Salinities and Temperatures…Really…
and Does It Matter?[/url]]The bottom line for salinities is simple. There is simply no reason at all to maintain the salinities of our systems below normal reef conditions. All reef inhabitants will suffer damage from prolonged exposure to lowered salinities. Invertebrates kept at low salinities often die within a few days to a few months. Given that corals, sea anemones, sponges and some other invertebrates have no old age or senescence (or to put it another way, they are immortal), low salinities result in a quick death. Some mollusks, crustaceans and most fish kept at low salinities die of kidney failure — it just takes them longer. A fish that dies in a couple of years in a aquarium may have had the potential to live more than 20 years had the salinity been appropriate.

 

[Terry B]

I think that Ron's remarks hold true for invertebrates. However, they are not true for teleost marine fish. Ron and I discussed this over drinks about 5 years ago at a convention in Vancouver Canada. I am surprised if he would still hold to that view for fish.
Here are some references, but there are certainly more.

Marine teleost fish are more euryhaline than previously believed (Wu & Woo, 1983).
Studies indicate that many reef fish which have been classified as stenohaline exhibit considerable powers of euryhalinity (Wu & Woo, 1983. Woo & Chung, 1995). Physiological assessment indicates that a species may be physiologically euryhaline while ecologically stenohaline. This suggests that the assignment of a species as euryhaline or stenohaline should be dissociated from a consideration of the ecological habitat of the species (Woo & Chung, 1995).

Ancient seawater concentration was believed to be much lower (404mm) than that found today (1123mm) (Spaargaren, 1979). It is likely that future coral reef inhabitants evolved in an environment that was much less saline than present day seas (Moyle, & Cech, 1982). This may account for the ability of marine teleost fish to readily adapt to hyposaline conditions. Cheung, et. al., 1979 determined that boney reef fish can be kept at a salinity (not SG) of 16ppt "indefinately."

A report in Drum and Croaker stated: “We now have experience that proves that a wide variety of teleosts can live quite comfortably at ½ salinity (1.010) for extended periods of up to 2 to 3 months (Goodlett & Ichinotsubo, 1997). Emperor angelfish Pomacanthus imperator were the subjects of one such study. They were kept in salinities as low as 7ppt for 30 days without any apparent ill effects (Woo & Chung, 1995).

Terry B

 

[reefrunner69]

Ancient seawater concentration was believed to be much lower (404mm) than that found today (1123mm) (Spaargaren, 1979). It is likely that future coral reef inhabitants evolved in an environment that was much less saline than present day seas (Moyle, & Cech, 1982). This may account for the ability of marine teleost fish to readily adapt to hyposaline conditions. Cheung, et. al., 1979 determined that boney reef fish can be kept at a salinity (not SG) of 16ppt "indefinately."

This actually bears out something else that I read recently. That due to evaporation...the ocean is actually getting more saline everyday, the amount it goes up is simply so infintesimal that it is not noticed except on a very large timeline. Very cool!!

 

[Terry B]

I am not sure just how cool it is if we are losing water every day that is not replaced.
Terry B

 

[reefrunner69]

Sorry, I meant it was cool to find something that "sort" of verified something you read elsewhere, in such a short space of time. I'll go find the quote I found and post it

 

[reefrunner69]

Why doesn't the ocean get saltier from evaporation like our tanks do?

'Cause it gets less salty from all the rain.

Nope, Most of that rain falls on land and then carries even more salts down to the ocean.

Here you go: http://www.windows.ucar.edu/tour/link=/earth/Water/salinity.html&edu=high

"So, the oceans are getting saltier every day...but the rate of increase is so small we can't even measure it yet!"

"Salinity of the top layer of the ocean is closely linked with precipitation and evaporation. Evaporation leaves behind dissolved salts increasing salinity and precipitation "freshens" the top ocean layers. So, salinity is high in mid-latitudes where evaporation is high and precipitation is low. Salinity is low near the equator because precipitation is so high. Very high latitudes can also see decreases in salinity where sea ice melts and "freshens" the water."

Then you can get into the striations of salinity in a given column of water; it's WAY more complicated than I thought...