MSU Electric Fish Lab

Getting Ready to Hatch!

Here we go! The eggs have developed another day, and now the body parts are in full definition. Viewing under the microscope, you can see blood pumping through the circulatory system in vivid detail, as well as lots of movement of the fish embryo as it gets ready to push its way through the eggshell (chorion) and into the world! Also notable are the otic vesicles, the ears of the fish, which show up as a pair of dark circles on the sides of the larval head. While the eye is formed, it is not pigmented yet. In about another day, the eye will be visible.

In the first image below, you can see the future ear (show by arrow) notice how the tail is now fully free of the embryo. Powerful full body movements and a weak eggshell (chorion) mean that this fish is ready to hatch!


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Hatching and eye development