question stemming from Habibs new article on heavy metals

[Anonymous]

see article here:
http://www.advancedaquarist.com/issues/ ... eature.htm


I posted my question on RC that stems from this article and would like to know peoples thoughts on the following:
this isnt a question on salt but while reading this article I had an idea-


quote:
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A very good antidote for cyanide poisoning is the administration of an iron salt. Cyanide will then react with this iron and not with the haemoglobin’s iron thus reducing the toxicity of the cyanide.
The free ionic cyanide is thus toxic, but the iron cyanides in general are not. There are many forms of iron cyanides and hexacyanoferrate is an example for this.
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With the problem of Cyanide caught fish- would it be possible to set up a quarantine tank for a fish that is known to hail from waters where the risk/odds are that it was caught by Cyanide catch, and dose said tank and fish with an Iron Salt such as described above?
I know that for humans, the antidotes for cyanide poisoning are:ferrous sulphate dissolved in aqueous citric acid, and aqueous sodium carbonate given orally, amyl nitrate by inhalation, and intravenous dicobalt edetate (Kelocyanor). Each of these are considered dangerous and are only administered by hospital staff, but would the introduction of hexacyanoferrate or something similar be an idea to prevent the mortality of cyanide caught fish?
I by no means acknowledge any justification of the use of cyanide as a means to catch fish for our hobbies, but there are fish I would love to keep, and when I ran my LFS there were fish I would NOT order because of the prevalence of cyanide use in the areas that are the habitats for said fish(ie, the Phillipines).

 

[Adam1]

budhaboy,

My guess would be that if a fish is cyanide collected and it survives collection, typical crappy handling, shipping, no food, etc., it isn't going to die down the road from the cyanide.

Cyanide works by blocking hemoglobins ability to transport oxygen. The greatest oxygen deprivation a fish will experience is transshipment.

Don't get me wrong, I am sure that some fish make it into our hands and then die from being cyanided. But doesn't it make sense that a collector/middleman/exporter that is irresponsible enough to perpetuate cyanide use is also going to be irresponsible in the way they handle the fish after collection? After all, it is primarily the Middlemen for the most part that provide the cyanide.


I think the bigger issue is to be able to test for cyanide. The only effective way to stop cyanide collection is for wholesalers to be able to identify and refuse cyanided fish on arrival.

It won't take many refused or unpaid shipments for the exporters, middlemen and collectors to get the message that they must stop cyanide use or they aren't going to get paid.

just my .02

Adam

 

[delbeek]

As was pointed out in the previous answer the problem is not cyanide in the fish when you get it, but the damaged caused by the cyanide when the fish is first exposed to it and the resulting consequences ... see Herwig's work in FAMA in the 70's and 80's on the damage done to the digestive tract of fish after exposure to cyanide.

The problem with cyanide detection is that the form of cyanide found in fish changes rapidly as Habib has mentioned it becomes complexed with other compounds rather rapidly.

The only real "cure" for cyanide poisoning in fish is NOT to use it in the first place.

JCD

 

[Anonymous]

I have only been able to find direct, documented information on the effects of cyanide (via Google) on aquarium fish, and it only spoke of destruction to the digestive tract. Is it also destructive via affecting the hemoglobin?

 

[Anonymous]

this is what I expected, but not being an expert on biological mechanisms, I thought I should cofirm my suspicions...

 

[Habib (Salifert)]

The cyanide and iron part of the article was just meant to show a relationship between speciation and toxicity.

When you receive fish caught using cyanide then a lot of damage is already done.

FWIW and I don't know how correct this is but the body tries to detoxify cyanide by converting it to thiocyanate (SCN-). This is less toxic and is excreted very slowly by the body. Stress in fish can cause lowering of the blood pH so does the CO2 in the water during shipping.

Reduced pH can convert SCN- to cyanide again.

The fish must be going through a hell.

Cyanide also damages corals so whne you get a cyanide caught fish then you are only seeing just a fraction of the real damage.