Baby zebrafish mortality

christian lawrence clawrence at
Tue May 17 04:24:00 EST 2005


Hi Joseph,
Both fertilization and mortality rates in larval zebrafish are largely 
dependent upon the condition of adults.  General condition of adults is 
determined by the environment and genetic background.   In general, you 
can typically maximize fertilization and larval survival rates by 1) 
careful maintenance of strains (maximizing # of contributors to each 
generation in wt, faithfully outcrossing transgenic and mutant lines, 
etc.), 2) feeding the fish a balanced diet that contains acceptable 
levels of unsaturated fatty acids and essential vitamins (live brine 
shrimp augmented with a good formulated dry food is usually
sufficient), and 3) maintaining water quality within stable, favorable 

Adults in poor condition will produce offspring of poor quality, if  they
reproduce at all.

You should also be cleaning eggs after collection on day 0 and day 1 to 
minimize protozoan and fungal infestations.  By "cleaning", I mean that 
you should be transferring "good" (alive) eggs into fresh fish water or 
embryo medium on day 0 and again on day 1.    After day 1, the embryos 
should be ok without cleaning until swim-up (day 5-6 @ ~28C).

Best of luck,

Christian Lawrence
Brigham and Women's Hospital
Division of Hematology
Karp Family Research Laboratories, 06.004B
One Blackfan Circle
Boston, MA 02115
Tel: 617.355.9041
clawrence at


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