QT - hyposalinity

[Kevin1000]

I am a few weeks from stocking my tank and it is time to set up a QT.

Need some advice.

First - I was thinking about keeping the QT in a hyposalinity state - if this makes sense I assume my cheapo hydrometer isn't going to make it. If so, does someone have a recommendation about what I should purchase w/o breaking the bank.

If keeping a QT in a hyposalinity state does not make sense I would like to know.

Thanks for your help

 

[cdeakle]

You should just do a quarentine tank (not hypo) with normal tank parameters unless your pretty sure the fish has ich. In that case then go for the hypo. After sufficient time in the quarentine tank it should be evident if your new buddies have ich.

You definately need a refractometer for hypo and its a good idea to get one either way. After getting my spiffy new refracto from MARINEDEPOT.COM I found out that my tank salinity was much higher then I thought because my damned swing arm was almost dangerously off.

 

[Kevin1000]

Thanks for the response.

Any recommendation on a reasonably priced refractormeter?

 

[Terry B]

I have been researching in some scientific journals about my idea of shipping reef fish in hyposaline waters. Hyposalinity counteracts osmoregulatory disturbance which is an inherent part of stress in fish.
I have long advocated routinely treating all newly acquired boney reef fish with hyposalinity therapy during the initial quarantine period. I believe this will greatly increase the survival rates of these fish. Hypo accomplishes many things for the fish. It' s not just for treating ich.
Terry B

 

[cdeakle]

I stand corrected!

 

[Kevin1000]

Thanks Terry. Any recommendation on a reasonably priced refractometer?

 

[wade1]

counteracts osmoregulatory disturbance which is an inherent part of stress in fish.

Hypo accomplishes many things for the fish. It' s not just for treating ich.

Before handing out blanket statements, lets qualify them some. Hyposalinity is EXTREMELY stressful for marine fishes (not an issue with many euryhaline species). The point of shipping fish in hyposalinity is a valid one due entirely to the buildup of ammonia in the small container. It will help the fish after it has been in transit for a while to maintain homeostasis.

Its use in a QT is something I always tell people to avoid unless necessary. It adds a huge stress to the fish (who are not adapted to dealing with low ion content of water and suddenly have to flush their kidneys almost constantly in order to keep up blood homeostasis). In normal conditions, marine fish "drink" water to keep up blood ions, wheras freshwater fishes have to keep exporting that water as it enters their body unasked for.... to place a fish from a reef into a hyposaline environment means that that fish suddenly has to work extremely hard to maintain that blood osmolarity. So, you are adding more stresses to the equation. Lets not forget that confinement stress is very real in many species.

A QT tank is just that. Its used for holding, at ideal conditions, fish until you are certain they are safe/disease free. If you wish to treat, it then becomes a hospital tank. At which time, hyposalinity is useful for some diseases and not for others. But, hyposalinity does not negate the need to maintain a 8-8.3 pH and temperature. I'd also hesitate to go below 28 ppt salinity range.

Wade

 

[Kevin1000]

Wade

Thanks for your input.

Seems like I have an ICK expert and the Site Admin on opposite sides of this issue - Of all the things that have changed in SW over the years I suspect differing opinions is not one of them.

I probably got the idea for a hyposalinity QT from reading one of Terry B's articles or post. I liked the idea because on one occasion in the past ICK has gotten into my tank even using QT. Kinda thought it was one more layer of protection.

If I go the std route (change to hypo only if I see something) would you recommend a freshwater bath prior to insertion into the show tank. (always looking for one more layer of protection)


Once again thanks for your input.

 

[wade1]

IF you do a quick dip on a healthy fish, it shouldn't be too bad, but don't go freshwater... again I'd only suggest going to half strength seawater at worst. But the dip should not last long.

As for the site admin, ignore it. I'm just drawing on what I know of fish physiology and aquatic toxicology.... site admin aside.

Wade

 

[Kevin1000]

Thanks for you help!

 

[Revstarky]

I tend to agree with Terry. I believe, and this is just my opinion, that the stress of hyposalinity is often overstated. It seems very possible that the stresses of infection, shipping, poor water quality, and physical injury many marine fish endure during collection are likely to result in dehydration. I have never seen a boney fish respond negatively during treatment in a hyposaline environment. It’s my understanding that saltwater fish live in a hypertonic solution their entire lives, and they are daily “stressed” to maintain homeostasis.

 

[Kevin1000]

Thanks

 

[Terry B]

Wade,
First, I want to say thank you for your participation and comments. This should make an interesting and informative exchange for all of us.
Do you have any evidence or reports from the scientific journals to support your contention that hyposalinity is extremely stressful for marine fishes? I have studied stress in fish extensively, have some scientific literature on the subject and I have written a dozen published articles on the subject myself. We seem to have very different opinions. Have you read any of the following?

Iwama, G.K., Pickering, A.D., Sumpter, J.P., Schreck, C.B. eds. Fish Stress and Health in Aquaculture. Cambridge University Press, New York, NY, 1997.

Evans, D.H. “The Roles of Gill Permeability and Transport Mechanisms in Euryhalinity.” Fish Physiology, 10, part B (Hoar, W.S. & Randall, D.J., Eds), pp. 239-283. New York Academic Press. 1984.

Goodlett, R. & Ichinotsubo, L. “Salinity and pH Adjustments for Quarantine Procedures for Marine Teleost Fishes.” Drum and Croaker, 28, 23-26, January 1997.
http://www.colszoo.org/internal/drum_cr ... f/1997.pdf

Bartelme, T.D. "Understanding and Controlling Stress in Fish: Part One," Freshwater and Marine Aquarium Magazine, February 2000a.

Bartelme, T.D. "Understanding and Controlling Stress in Fish: Part Two," Freshwater and Marine Aquarium Magazine, March 2000b.

Donaldson, E.M. “The Pituitary-Interrenal Axis as an Indicator of Stress in Fish.” In “Stress and Fish” (Pickering, A.D. Eds.) pp. 11-47. Academic Press, London. 1981.

McDonald, D.G. & Milligan, C.L. “Chemical Properties of the Blood.” In Fish Physiology, 12(B), Hoar, W.S. Randall, D.J. & Farrell, A.P. (eds.), 55-133. Academic Press, New York.

Mazeaud, M.M. Mazeaud, F. & Donaldson, E.M. "Primary and Secondary Effects of Stress in Fish: Some New Data with a General Review," Transactions of the American Fisheries Society, 106, 201-12, 1977.

Mazeaud, M.M. & Mazeaud, F. "Adrenergic Responses to Stress in Fish," Stress and Fish, Pickering, A.D. Ed. Pp.49-75. Academic Press, London, 1981.

McDonald, G. & Milligan, L. “Ionic, Osmotic and Acid-Base Regulation in Stress.” In Fish Stress and Health in Aquaculture (ed. By Iwama, G.W. Pickering, A.D. Sumpter, J.P. and Schreck, C.B.), pp. 119-144. University Press, Cambridge, UK. 1997.

Moyle, P.B. & Cech, J.J. Jr. “Fishes---An Introduction to Ichthyology.” Englewood Cliffs, N.J: Prentice-Hall, 1982.

Murai, T., Andrews, J.W., & Muller, J.W. "Fingerling American Shad: Effect of Valium, MS-222 and Sodium Chloride on Handling Mortality," Progressive Fish Culturist, 41(1), 27-29, 1979.

Pickering, A.D. & Pottinger, T.G. "Stress Responses and Disease Resistance in Salmonid Fish: Effects of Chronic Elevation of Plasma Cortisol," Fish Physiology and Biochemistry, 7, 253-8, 1989.

Spaargaren, D.H. “A Comparison of the Composition of Physiological Saline Solutions with that of Calculated Pre-Cambrian Seawater.” Comparative Biology and Physiology, 63A, 319-323, 1979.

Wedemeyer, G.A. "Handling and Transportation of Salmonids," Principals of Salmonid Aquaculture. Pennel, W. & Barton, B., eds., Elsevier Publishing, Netherlands, 1996.

Wedemeyer, G. "Some Physiological Consequences of Handling Stress in the Juvenile Coho Salmon and Steelhead Trout," Journal of the Fisheries Research Board of Canada, 29(12), 178-1783, 1972.

Woo, N.Y.S. & Chung, K.C. “Tolerance of Pomacanthus imperator to Hypoosmotic Salinities: Changes in Body Composition and Hepatic Enzyme Activities.” Journal of Fish Biology, 47, 70-81, 1995.

Wu, R.S.S. & Woo, N.Y.S. “Tolerance of Hypo-Osmotic Salinities in Thirteen Species of Adult Marine Fish: Implications for Estuarine Fish Culture.” Aquaculture, 32, 175-181, 1983.

The works by Woo & Chung, Wu & Woo, Moyle and Cech, and Spaargaren may be of particular interest to you.
Terry B

 

[Anonymous]

Personally, I cannot cite studies, I can only cite my own experience. And that has been that, in very general terms, hyposalinity and freshwater dipping are not as stressful for most boney fishes. This is not to say all, clearly there are exceptions.

I would also like to point out that many fishes we might generally consider to be entirely marine, are, in fact, fishes that regularly tolerate brackish to darn near fresh situations (even some cartilagenous fishes!). One that comes immediately to mind is C. loricula (flame angel).

 

[wade1]

Terry-
Thanks for the literature citings. I have indeed seen a few of those as I do research into fish stress (more relative to oxidative stress) in estuarine species (as my PhD project). I did note that many of the listed articles deal with euryhaline fishes, but I'll certainly pull up and look through some of the rest.

I'm basing most of my comments on the changes in blood chemistry and the production of both sharp increases in cortisol and the reduction in some immune measurements that I have seen and discussed with some of our fish vets at the university.

I am going to say that I generalized in order to reduce the promotion of hyposalinity treatments to the layperson. Instead, perhaps, I should have put forth a method for proper hyposalinity treatment.

My point in the contention of stress is a valid one, however. If a fish is already stressed, adding the shock of ionic regulation will not benefit the animal at all. Secondly, hyposalinity as a "treatment" is typically only valid on external parasites.

At any rate, thank you for the citings. I'll certainly give them a read.

Wade

 

[Revstarky]

See, now this is getting interesting. Wade, you mention that your current area of study is concerning oxidative stress. Have any of the vets you’re discussing these matters with performed controlled studies of marine fish using specific gravity as the only variable to check if this alone elevated cortisol for a prolonged period? If so, that knowledge would be a great help

 

[wade1]

Our lab has used Atlantic Menhaden (a euryhaline species found in a wide range of salinities) and Nile Tilapia in salinity stress studies. Menhaden showed very little significant effects, whereas Tilapia showed much more negative impact. The data is being worked up (unfortunately, the grad student responsible just had a child) and will be submitted eventually.

Wade

 

[Terry B]

Wade,
I know this is going to be controversial, but anything contrary to conventional wisdom always is in the beginning. You will find as we go along that I can give support for my ideas. I am informed about stress in fish (including stress hormones, etc.), fish diseases and immune function. I am not claiming that I know everything that there is to know, but enough that is pertinent to our subject of hyposaline conditions.

I would be happy to refer you to some of the articles that I have written. Your own Advanced Aquarist Online magazine recently featured an article that I wrote about immune function and a biological defense modulator. My guess is that most people had never heard of it before. I was able to provide more than an ample number of scientific references to support it. I was considered a “radical” or even “crazy” several years ago when I started popularizing hyposalinity therapy on the internet and in the hobbyist magazines. Now those people use me as a reference for their own work. Please bear with me and you will find that although I have some ideas that are new to many there is evidence to support them.

It is also noteworthy that manipulating the salinity is a common practice among fisheries as a means of alleviating the stress of handling and transport. They would not be using it as a way to control stress if hyposaline conditions (within some limits) caused stress. While I would agree that, many unnatural environmental conditions do induce stress and the subsequent release of stress hormones into the blood stream we should not make a blanket statement that all such conditions in this category induce stress.

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.
Terry B

 

[wade1]

TerryB-
I'm not arguing anything here except caution (at least at this stage since I have yet to read the references you listed).

As for promoting hyposalinity, you are more than welcome! I will, however, caution anyone I can to avoid that additional 'treatment' whenever possible. Even if what you believe and seem to be experimentally indicating is true - that marine teleosts can indeed withstand or not be stressed by hyposaline conditions.

The bottom line for me is overall animal health, and any treatment beyond the absolutely necessary is an added stress. If there is overt disease, then treatment must be made. If there is not, and its in fact only quarantine we are discussing, then I promote the absolute minimal additional stress (including size restrictions, temp, pH, DO, salinity, etc). The closer to 'normal' environmental conditions, the better.

I'd love to continue the debate, but at this point I haven't read up as far as I would like and my experience is limited to 2 species (those not very relevant) and discussions with veterinarians.

Glad to know that someone is bringing science into the debate though!

Wade

 

[Anonymous]

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