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(Source: E. Sullivan from Zebrafish Book 5th Edition)

This method requires more work, but is especially well-suited for production of large numbers of embryos (upwards of 1000 embryos per tank) once or twice a week.  A continuous supply of embryos can be obtained with this method by adding more tanks of fish and rotating the schedule among the tanks. Although zebrafish reach sexual maturity at 10-12 weeks, the breeding fish should be between 7 and 18 months of age.  Keep males and females in separate tanks with up to 8 females or 16 males per 10 gallon tank. The tanks should be cleaned at least once per day by siphoning, replacing about 1/3 of the water. Feed the fish 2-3 times per day. On the day before you want embryos, 1-2 hours before the end of the light period, feed the fish and clean the tanks.  Then transfer the males into the tank with the females at a ratio of 1 male to 2 females (excellent results come from 4 males and 8 females).  Add marbles to cover the bottom of the tank a single layer deep.  After the beginning of the next light cycle, collect the embryos by siphoning the bottom of the tank (see Embryo Collection).

After collecting the embryos, transfer the males back into their tank, scoop out the marbles with a net and clean them thoroughly by autoclaving or by soaking them for 4 hours in a 10% solution of bleach followed by a 4 hours rinse in running water.  Do not collect embryos more than two days in a row from the same fish and remove the marbles for at least a week between embryo collections. Transfer all fish to new aquaria every 10 days and scrub and bleach the old tanks.

1 Comment

  1. Anonymous

    I have a large batch of zebras at my university and I am having a lot of difficulty in breeding my fish. I am following this very method described here. I keep the fish at about 28 degrees Celsius and give them the 14- hours-light, 10-hour-dark cycle. But I don't know why I'm not getting any results. I breed each batch within an interval of 15 days. I give them high-protein Zeigler feed as well as live artemia. 

     I have spoken to other colleges and a few research facilities who have been following the very same procedure under the same conditions and are getting excellent results. 

     My research is going a little too slow because my fish fail to breed every single time. I've only gotten about 3-4 viable broods since last year. I have tried IVF, but it's not always the best thing as it doesn't always work (I learn't that the hard way;I had done a batch of IVF and had successfully obtained about 60 fertilized eggs, but they all suddenly died after 4 hours). 

    Any ideas on how I can get me some fertilized eggs?

    Thanks a ton...