Cmon Syd, you are being a bit obtuse here. When was the last time you saw a mercury thermometer in a fish tank or an LFS? They are pretty uncommon in domestic applications now. Everything is either alcohol or digital.
For malachite green to not contain copper, it would have to not contain malachite, which as you know is a cuprous mineral. Granted, it might not, but I guess it's a natural mistake if I have made it. I would have assumed something called malachite green might contain malachite. If I'm wrong, then
mea culpaAlso, I think it could be supported that neither would kill fish in minutes and certainly not so dramatically.
kleinz you will find the heavy metals come in via your mains water... we all get them but to what extent we dont know... there are guidelines as to what is suitable for human consumption and what is not... most of these heavy metals are all around us and they will find their way into our dams and ground water......
and for the comment of heavy metals take a long time to kill is really off the mark.... drink a glass of mercury and see how long you last!!!! its all about how much quantity is present in your water and your fishes tolerance of these heavy metals....
Johnno, mercury was widely (mis)used in medicine for millennia. The king to whom that terracotta army belongs took it as a tonic. Isaac Newton used it. It was common to use it as a purgative or as a treatment for syphilis. I think it was taken for cholera. They drank it by the glass and lasted years. True, it did nasty things, but not overnight.
Sugar was really scarce in the Roman world so they used to put lead acetate, which has a sweet taste, in their wine. Prolly killed quite a few of them and sickened way more, but not quickly or they wouldn't have had time to , you know, build an empire and all that.
It's not quick. Really. It's not.
That's how fish manage to accumulate large enough amounts to be a danger to us eating them. In the tropics, you should be really careful about eating sharks, because the amount of mercury in them is huge.
As for tap water, it's treated and tested. It's not hard to find out what's in it. The acceptable levels of heavy metals are pretty low and I imagine if there was any more than a smidge of any of them the water board would chelate the hell out if it. Groundwater in a city is always suspect, and roof runoff would vary widely, but if scheme water was off we would see evidence in the health of the population by now.
Copper. Copper might be different. I'm not sure. It's certainly death for a lot of inverts. I think it would be less dangerous in an alkaline environment like a Rift Lake tank , but the acid flux might well have resulted in a lot of free copper at once. That's all I can think of. I don't know enough there. If they were gasping and it is copper, perhaps it affects blood or gills adversely. But given that Buccal had flushed extensively first and it was so quick... I dunno. You'd expect that kind of effect from a litre of bleach, but not a smidge of copper surely.
Anyway this is all academic and killing time until the main even which is when HYPANHEAVEN PRODUCES THE AWESOME MUTANT FISH PIX WE ARE ALL HERE FOR!
ps. If you are epileptic: sorry about that...
Edited by Kleinz, 07 October 2012 - 08:26 AM.