[Zbrafish] Water chemistry

[Bill Trevarrow]

Hi Rene,

There are no simple answers to this.

Copper and zinc toxicity are influenced by the hardness/softness of the water.
The softer the water, the lower the dose of zinc 
or copper that can affect your fish.
The toxicity varies with the kind of fish and as 
we all know there is little of this kind of 
specific information available for zebrafish.

Zinc is less toxic than copper, which is good in 
your case, but your numbers are not that far from 
levels that can cause problems in some kinds of 
fish in some situations.

You might also want to check for other potential 
metals in your water and possibly determine where 
the zinc is coming from. When we had problems, 
copper and zinc water coming from new copper 
pipes. it was greater in the hot water lines and 
jumped up in concentration after going through a 
non-stainless steel heat exchanger (water heater).

We successfully used RO machines to remove copper 
and zinc from the water we used. Resins to remove 
the copper and zinc lowered the copper and zinc 
concentrations but also lowered the water 
hardness so much that the metal toxicity 
increased.

If you want to do a test, set-up an aquarium with 
water from a zinc free source, while holding all 
other factors as similar as possible, and compare 
relevant results (survival, growth, egg laying, 
or symptoms listed in the ZIRC link for copper) 
after a week or two.

Some references:
Copper:
http://zebrafish.org/zirc/health/diseaseManual.php#Copper%20Toxicity

Copper and other metals:
G. Wedemeyer, Physiology of Fish in Intensive Aquaculture


>We may still have a problem with our water chemistry. Does anyone know
>if 100 µg/l Zinc is suitable for zebrafish?
>The company claims that this not a problem. However, fish specialists
>say it's too much.
>What do you think?
>Thanks in advance for your help!
>
>_______________________________________________
>Zbrafish mailing list
>Zbrafish from net.bio.net
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--

Bill

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Bill Trevarrow
Institute of Neuroscience
University of Oregon 1254
Eugene, OR 97403-1254
Off. Tel: (541) 346-4598
Cell: (541) 844-9054
Fax: (541) 346-4548
e-mail: trevarro from uoneuro.uoregon.edu
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