No eggs/embryo from zebrafish

Dallas Weaver, Ph.D. deweaver at
Mon Jun 16 10:28:40 EST 2003


The first question that comes to mind is what is the pH the next day 
after you aerated a sample?  If you just add NaHCO3 and HCL, the 
CO2 partial pressure could be very high and that would decrease the 
interest in breeding.  Free CO2 above about 20 ppm can be a problem. 
Most zebra systems don't have CO2 problem and you won't find much 
in the zebra literature (you will in the aquaculture literature and 
chemical engineering literature). This can really get into some 
complicated water chemistry involving the entire carbonate, bi-
carbonate, carbonic acid, free CO2 systems as functions of pH and 
alkalinity.  If you provide the pH after your adjustments and the pH after 
extensive aeration using outside air (360 ppm CO2 partial pressure) 
along with temperature and salinity, I could plug the numbers in my 
spread sheet and give you the alkalinity and CO2 partial pressure, free 
CO2, etc.  

Most tap water is fine the way it is if it doesn't have chlorine or 
chloramines.  If you run the tap water through activated carbon with a 
10+ minute contact time and then aerate the water in a large container 
for a day or so, it should be fine.  

Dallas E. Weaver, Ph.D.                     Scientific Hatcheries
deweaver at                            5542 Engineer Dr.
714-890-0138                                Huntington Beach, CA Fax
714-890-3778                                   92649

in article bcdn74$rae$1 at, Andrew  Nartey at
anartey at wrote on 6/13/03 4:37 PM:

> I've been unsuccesful for the past month in trying to get eggs from
> our zebrafish. I feed them brine shrimp everyday and change their
> water 3x/day. For water I dechlorinate normal tap water and add
> Sodium bicarbonate  and optimise Ph to 7 (with Hcl). I have not got
> any results as of date and I'm getting a bit disappointed. I  would
> like to know if there are any known  fish water recipes (using tap
> H20 and  not Distilled or  RO water). I would also like to know how
> breeding is done . I currently use the breeding dish method (in
> tank) and have been unsuccesful. Any kind of help or comment will be
> very much appreciated. 
> Thanks...  
> Andrew N.
> The Kings University College
> Edmonton, AB
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