Scientific HatcheriesFor spawning zebra fish we use a group spawning method with spawning trays being placed in the tank. This way, the fish are not moved or disturbed before spawning. Our experience, and a series of experiments, indicate that zebra fish prefer to spawn in shallow water with a little soft substrate (plant, garland, etc.). Fish that are not ready to spawn prefer to stay in deeper water and avoid all the activity. If all the fish are confined to a shallow water, some unripe females may be forced to spawn and will produce poor fertilization.
The spawning trays can be removed without a major disturbance to the animals (not being removed from the water) and the embryos collected for accurate staging. We use multiple trays for rapid replacement and continuous spawning. This way we can obtain before first cleavage eggs all morning without a great deal of effort.
It is probably best to explain the details by a series of photos.
Starting with the spawning tray in a 9L Aquaneering Tank.
After the desired amount of time (the longer the time, the more fish, the more eggs), remove the spawning tray. The eggs can be seen by holding up the tray and looking at the bottom of the screen. Note the placement of the garland on the screen held in place by a rubber band.
We just wash the eggs from the tray from the back side into a cup or other container. Depending upon when the fish were last fed and how clean your system is, there may be some fecal material and detritus in the tray. We handle that problem with a fine screen which will hold the eggs but pass most of the detritus. As long as you are gentile, screens do not damage the eggs.
Finished product of embryos in screen ready for bleaching or other processing. This was just a quick test for some photos with only a few fish in the tank and we obtained about 800 embryos by 10 AM.
