zebrafish questions

Christian Lawrence clawrence at rics.bwh.harvard.edu
Wed Aug 4 06:15:00 EST 2004


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Hi, I 've provided, brief general answers to your questions below (in
caps).  if you would like more specific info, let me know.


> --------------------------------------------------------------------------
>
> I am new to the zebrafish field.  I am in the process of setting up some
fish tanks in my lab.
>
> I have the following questions regarding this:
>
> 1.  How do you control the growth of algae in these tanks?  My tanks are
fitted with a mechanical, chemical (carbon) and biological (bio-wheel)
filter
DON'T OVERFEED THE TANKS, PARTICULARLY WITH A DRY FEED (IF YOU ARE USING
ONE).  YOU CAN ALSO PERIODICALLY SIPHON OUT DETRITUS IF IT ACCUMULATES.
LIGHT INTENSITY ALSO AFFECTS ALGAL GROWTH - THE BRIGHTER IT IS, THE MORE
QUICKLY IT WILL GROW.
DO 20-50% WATER CHANGES A FEW TIMES A WEEK TO FLUSH OUT EXCESS NITRATES.
MAKE SURE YOU CHANGE CARBON FILTER MONTHLY.
RINSE PARTICLE FILTERS MONTHLY OR BIMONTHLY IF YOU HAVE THEM.
>
> 2.  How often do you need to clean out these tanks completely?
SHOULD CLEAN OFF THE ALGAE PERIODICALLY (WHEN IT GETS THAT YOU CAN'T SEE
IN THE TANKS).  SIPHON OUT DETRITUS.  PERIODICALLY CLEAN AREAS OF TANK
ABOVE WATER (LIDS, INSIDE ABOVE WATER LEVEL, ETC.).  IF YOU CAN SWAP OUT
THE TANK EASILY ENOUGH, YOU CAN DO THIS EVERY SIX MONTHS OR SO.  CLEAN
DIRTY ONE WITH MILD BLEACH SOLUTION, RINSE VERY WELL, AND SWAP BACK IN
ANOTHER SIX MONTHS.  THIS SWAPPING HAS TO BE DONE QUICKLY SO YOU DON'T
KILL YOUR BIOFILTER.  ALGAE IS NOT HARMFUL TO THE FISH, BUT ANIMAL USE
COMMITTEES LIKE TO BE ABLE TO SEE INSIDE TANK(S).
>
> 3.  What is the alternate method of collecting embryos besides using
marbles at the bottom of the tank?
YOU CAN PURCHASE BREEDING CAGES FROM ONE OF ANY NUMBER OF SUPPLIERS
(AQUATIC HABITATS, AQUACULTURE SUPPLY, ETC.)  THE GENERAL DESIGN CONSISTS
OF A 1-2L PLASTIC TANK AND A BREEDING CAGE WHICH FITS INSIDE. CAGE HAS
MESH OR GRATED BOTTOM. FILL THESE TANKS WITH FRESH FISH WATER, AND PUT
PAIRS OR SMALL GROUPS OF MALES AND FEMALES IN THE AFTERNOON/EVENING BEFORE
THE MORNING YOU WANT THEM TO SPAWN. FISH SPAWN, EGGS FALL THROUGH AND
CANNOT BE EATEN, AND YOU HAPPILY COLLECT.

>
> 4.  Since males and females are housed separately (though I have problem
identifying males and females clearly) is bringing them together 24h
before collections of eggs enough time for them to breed?
ONCE YOU BECOME FAMILIAR ENOUGH WITH THESE FISH, YOU SHOULDN'T  HAVE A
PROBLEM DISTINGUISHING MALES FROM FEMALES.  HEALTHY, REPRODUCTIVELY ACTIVE
MALES WILL BE STREAMLINED IN SHAPE AND BRIGHT YELLOWISH ORANGE IN COLOR. 
FEMALES WILL BE SILVERY IN COLOR, WILL HAVE LARGE ROUNDED GUTS (BODY
CAVITY FILLED WITH DEVELOPING EGGS), AND ARE TYPICALLY A LITTLE LARGER
THAN MALES. IF YOU CONTINUE TO HAVE A HARD TIME TELLING THEM APART,
CHANCES ARE THAT THEY ARE NOT IN VERY GOOD BREEDING CONDITION.  SOME
STRAINS ARE A LITTLE HARDER TO SEX (TUBINGEN LONG-FIN (TL), WIK).
IF YOU ARE KEEPING SEXES SEPERATE, MAKE SURE TO BREED FISH EVERY WEEK OR
SO.  SETTING THEM UP THE NIGHT BEFORE YOU WANT THEM TO SPAWN IS
SUFFICIENT.
>
> 5.  Do you need to feed the fish before collecting the eggs that morning
or that can wait till after collection?
DO NOT FEED FISH IN THE AM IF YOU WANT THEM TO BREED THAT DAY,
PARTICULARLY IF YOU USE AN OUT OF TANK SET-UP METHOD (DESCRIBED ABOVE). 
FEED THEM 2-3X PER DAY, LATE MORNING, EARLY AFTERNOON, LATE AFTERNOON.  IF
YOU USE BREEDING CAGES, FEED A FEW HOURS BEFORE YOU SET THEM UP IN THE
EVENING.
>
> Thanks much for all the help.  Any suggestions are welcome to make my
entry into this field smooth.
>
> Regards,
>
> Lakshmi Sivaraman
> Principal Scientist
> World Wide Safety Sciences
> Pfizer Global Research & Development, 0216-300-425.2
> 7000 Portage Road, Kalamazoo, MI 49001
> Phone: 269-833-8305  Fax: 269-833-7722
> lakshmi.sivaraman at pfizer.com
>
>
>
Chris Lawrence

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