Osmotic Shock

[OllieNZ]

I came across this article http://www.tbas1.com/Exchange/The New England 11.pdf posted on another forum and among other things it discusses osmotic shock and the effects it has on fish health in particular causing gill damage. I found this quite interesting and it may explain why we have issues with some delicate fish species, otos come to mind.

Anyone else got thoughts on this?

Regards

Ollie

 

[dw1305]

Hi all,
I'm not sure about Otocinclus, I think it is a combination of factors that lead to them being difficult to acclimatise, but they certainly need good quality water. I'm sure if they were fed with vegetables when in transit, the shop etc they would survive much better. You can actually find it is nearly all the herbivorous (aufwuchs feeders) loricariids (Gold Nuggets (Baryancistrus) etc) that are difficult to acclimatise, not just Otocinclus.

The article (by Joe Gargas) I hadn't seen before, but it is one of the best, and most readable, accounts of applicable water chemistry that I have ever read.

I'd like to think that LFSs in the UK are better at fish care than the examples from the USA he gives. I would have slight reservations about the post in that it is intended for the non-planted tank keeper, and as members of this forum have pointed out the adding 50ppm of NO3 to your tank is very different from 50ppm of NO3 being present from the oxidation of NH3 to NO3.

Personally I like to keep conductivity low for all soft water fish (less than 200microS) and I'm fairly confident that this is the successful recipe for the more difficult soft water fish, against that I think both Clive and Tom have kept tanks with soft water fish successfully where the conductivity has been in excess of 500 microS, so something other than a pure osmotic effect is going on.

cheers Darrel

 

[Fred Dulley]

Seeing as a lot of us came from TFF is it ok for me to post this? Knowledge is power.

http://www.fishforums.net/index.php?/to ... p__1692388

 

[dw1305]

Hi all,

Seeing as a lot of us came from TFF is it ok for me to post this? Knowledge is power.

It is freely available on the WWW, so I don't see there can be any real objection to posting the link. It is another good explanation of do you know who "Bignose" is/was?

I'm going to email Joe Gargas (from the link in the pdf), thank him and ask whether he has any more data. I'll ask both him and the NEW ENGLAND CICHLID ASSOCIATION whether I can add distribute Joe's article (with acknowledgement to the author and NECA names upon it).

cheers Darrel

 

[OllieNZ]

Hi All,
Thanks for the post Fred, it has helped me understand how the change in osmotic pressure works in the fish and why when it changes it causes stress.

so something other than a pure osmotic effect is going on.

Could this be to do with which elements are being swapped out during osomregulation?

The thing I found interesting was the fact that gill damage leading to death was more likely when the major cations and anions become sodium and chloride ions. Ive never had to treat sick fish so correct me if Im wrong but alot of remedies involve using or contain aquarium salt in one form or other which may make things worse?

IF salt is the issue (not saying it is) it is not an element we add to our planted tanks so even the heaviest of EI dosers would not cause their fish issues on that front.

Also could it be possible that the gill damage could be healed/reversed in any way or is it always going to be permanent?

Regards

Ollie

 

[dw1305]

Hi all,

Ive never had to treat sick fish so correct me if Im wrong but alot of remedies involve using or contain aquarium salt in one form or other which may make things worse?

I think it will nearly always make things worse, there is no reason why placing a fish from water that is very low in all dissolved salts in to salty water should make it get better, and there are much more efficient ways of removing external parasites etc.

It might help with a fish from hard, salt rich water that had been kept in water that was deficient in all alkaline metal ions.

IF salt is the issue (not saying it is) it is not an element we add to our planted tanks so even the heaviest of EI dosers would not cause their fish issues on that front.

I'm not sure that there is any scientific work on this, aquaculture doesn't tend to use plants, and species like Channel Catfish, Carp, Tilapia, Eels, Trout and Salmon are either tolerant of gross pollution or "euryhaline".

Soft water fish are very efficient at extracting the ions they need from water that is very low in dissolved salts, they don't need any help. My suspicion is that a lot of "RO reconstitution" mixes etc contain NaCl mainly as a filler, because it is very cheap to buy.

Also could it be possible that the gill damage could be healed/reversed in any way or is it always going to be permanent?

I think it probably depends on the nature of the gill damage whether the lamellae re-grow, they certainly can re-cover from minor damage.

cheers Darrel

 

[plantbrain]

Seems KH plays a larger role than just TDS to me.....I'm speculating.........but that would be my hunch.
I agree, that TDS alone/salt ppm does not explain everything.

The type of salt/TDS does I would argue. Some ions fish have an easier time keep in/out, same for plants.