breeding the old fashion way

Jane Cox coxj at slu.edu
Mon May 16 12:26:00 EST 2005


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Hi, Leslie, We have periodic problems with the fish laying. We think it
may  be seasonal, but have no hard evidence! Either that or they are not
laying  just to confound us.  We have a conductivity of 530 uS and a pH of
7.5,  using house distilled water, Instant Ocean (144mg/L), Sodium
bicarbonate (75  mg/L) and Calcium chloride (40 mg/L) final
concentration. You probably need to add more sodium bicarbonate to bring
up  the pH. We set up about 6 females and 3 males in 1 liter breeding
tanks and  about half of the crosses lay. Your nitrates may be too low -
you need some  nitrates to make sure the bacteria are ok - the nitrites
are the bad ones -  you don't want any of them!! So test your nitrites as
well as pH and  conductivity. Conductivity varies tremendously between
labs - anything from  150 uS to 2000 uS. The higher the conductivity,
usually you get less  breeding. Higher is good for squeezing fish for
eggs, but about 500-700 is  generally ok for natural crosses. Hope this
helps. Cheer, Jane

Jane Cox, Ph.D.
Dept Pharm. Phys
Saint Louis University Med. School
1402 Sth. Grand Blvd.
St. Louis, MO 63104
(314) 977 6445




From: "Leslie Day" <l.day at neu.edu>
Newsgroups: bionet.organisms.zebrafish
To: <zbrafish at net.bio.net>
Sent: Monday, May 16, 2005 11:42 AM
Subject: breeding the old fashion way


> --------------------------------------------------------------------------
>
> For the past couple of months our zebrafish have not been breeding very
well, if at all. Most of the fish are less than a year old. Our system
is a little archaic, 10 gallon tanks with whisper filters on the side.
We placed marbles at the bottom of the tanks and collect eggs by suction
in the morning 1-2 hours after lights come on. I am not really sure if
the breeding problem is the water conditions or the fish themselves.
>
>
>
> The water we use is instant ocean mixed with DI (2.4g/20L). We add in
some Kent pH stable (mostly bicarb) to maintain a pH of 6.5 - 7.0. Is
that too low?  The nitrate levels are very low. I am not sure what the
conductivity is supposed to be or how to adjust if it is not in a good
range.  Anything else I should be testing for?
>
>
>
> I must admit I am a bit of a novice and any help to decipher why the
fish are not breeding would be greatly appreciated.
>
>
>
> Much appreciated.
>
>
>
> Leslie Day
>
> Biology Dept.
>
> Northeastern University
>
> Boston, MA 02115
>
> l.day at neu.edu
>
> (617)373-3780
>
>
>
>
>
>
>
>


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