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Zebrafish Husbandry 101: Crossing Basics

In this short educational video, you will learn how to perform a zebrafish embryo injection and some tips and tricks you can use to ace your next injections.

Interested in learning more? You can view the rest of our Zebrafish Husbandry 101 series here, and learn more about our zebrafish services here.


When breeding zebrafish, we first have to sex them. Males tend to have a torpedo shaped body and brighter colors, whereas females are rounder, they have dull colors and they also have this ovipositor that the arrow is pointing towards. We set up breeding pairs the night before crossing them. The crossing cages have a divider dividing the males and females and a grate on the bottom that the embryos can fall through. This prevents the embryos from being eaten by the parents. The following day we will pull the dividers and move them to a lower volume of water and put them at an angle to simulate a slope in their natural environment. This can entice them to breed more so than being on a flat surface. Here are some breeding pairs that are very interested in each other and active. These embryos are falling through the great to the bottom of the cage where we can collect them.

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InVivo Biosystems

InVivo Biosystems provides essential services to help pharmaceutical, nutraceutical, biotechnology companies and academic research institutions around the globe accelerate their research and drug development efforts. An expert in CRISPR genome editing, InVivo Biosystems creates custom genome edited C. elegans and zebrafish models to enable aging and other disease studies. In addition, InVivo Biosystems provides in-vivo analytical services to produce data and insights for companies that need to make go/no-go decisions quickly in early-stage development of new compounds.

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