[Zbrafish] Fluke-tabs and spawning

christian lawrence via zbrafish%40net.bio.net (by clawrence from rics.bwh.harvard.edu)
Tue Mar 11 12:59:00 EST 2008

The symptoms you describe are generally associated with fish that are no
longer in reproductive condition (assuming that they were previously).  It
probably isn't the fluke tabs themselves that have caused this unless you
did not use them as directed or the brand you used is not appropriate for
the zebrafish.  Your problem (fish in non-reproductive condition) could be
and is likely to be the result of a litany of things working in synergy,

Advancing age
Prolonged stress (and resource allocation towards immune function and away
from everything else)
Diet (bad diet -- most likely culprit)
Poor "socializing" (leave the same reproductively active and healthy fish in
the same tanks at densities below 5 fish per liter for a long time with no
or little human intervention and watch what happens over the course of a
month or two).
Water quality (although you think it is fine, it may not be optimal)

To make improvements, go from the simple forwards:

1. Clean up your fluke problem.  This includes ensuring that you used the
tabs properly and that they worked.  
2. Ensure that all water quality parameters are favorable.
3. Ensure that your diet is complete and properly handled/administered.
Formulated feeds should be no older than 3 months from process date, stored
in sealed containers at 4C, and you should be feeding several different
things (Artemia and pellet or flake).
4. Look at the age of the fish.  Anything above 15 months is OLD and your
chances of "restarting" them are lower the older they are past this age.
This is particularly the case if you had a fluke infestation.  This type of
thing "ages" the fish and so a 15 month old fish that lived through a fluke
epidemic is much "older" than one that didn't.  
5. Improve social conditions.  Mix and match fish from different tanks when
6. Mate fish from disparate genetic backgrounds if possible.
7 (and 1a).  Get some new fish from a reputable source or (even better) rear
some yourself.

Good luck,



Christian Lawrence
Brigham and Women's Hospital
Karp Family Research Laboratories 06-004B
One Blackfan Circle
Boston, Massachusetts 02115
Tel: 617.355.9041
Fax: 617.355.9064

-----Original Message-----
From: zbrafish-bounces from oat.bio.indiana.edu
[mailto:zbrafish-bounces from oat.bio.indiana.edu] On Behalf Of martam
Sent: Tuesday, March 11, 2008 7:19 AM
To: bionet-organisms-zebrafish from moderators.isc.org
Subject: [Zbrafish] Fluke-tabs and spawning

Hi everybody,
I used anti fluke tabs to remove trematodes from our zebrafish colony.
I used the dosage recommended by the supplier, and it seems the treatment
worked well.
But, right now I have problems with zebrafish spawning and I am quite
Fishes seem to be healthy, but actually males do not look very "yellow" and
apparently females do not get gravid.
Has anyone ever observed anything similar? Does anyone have any suggestion
to improve spawning (water parameters are ok..)?
Thank you

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