We frequently do. We transfer the fishes from regular glas tanks into breeding tanks, give them time to acclimatize and then we remove the barrier between males and females. Each tank will yield from zero to about 500 embryos and more. We put up up to 15 breeding tank. Usually sufficient embryo numbers can be collected using this method.

Do you keep males and females in separate tanks when not spawning? 

Hey Phoebe, it depends. Usually for short periods you can either keep males and females in separate tanks or in the same breeding tank with the barrier. For longer period I have always found better to put fish back in their original tanks, unless they're specific transgenic or mutant lines. You just have to take extra care when keeping single males and females in separate tanks for longer period as I have noticed they tend to grow bigger and more aggressive.

Yes, we're currently playing with various zebrafish embryo protocols and we keep 30 fish (10 f/20 m) in a 50l tank with basic hobby equipment. Both sexes are kept in the same tank, they breed there frequently. When we need embryos we place 3-4 females with 7-8 males, the yield is usually 300-500 embryos/session. I suppose separating sexes would significantly increase production, but in our case there's no need.

Dear Phoebe, 

In our facility we keep fish in glass aquaria (aprox. 50 fish/tank). When we need eggs for experimental procedures, we place all the fish in a 'home-made' breeding box, which is basically a plastic structure surrounded by a net (very easy to make). The day before spawning, we place them in the box, which is almost as big as the tank. As a consequence, the fish experience a minimal amount of stress, leading to increased egg-production. Furthermore, we add a (plastic) plant to stimulate mating behaviour. Our yield ranges from a steady 600 eggs up to 3000+ eggs when the fish are at the optimal breeding age.  If you have any further questions (e.g. about making a breeding box), feel free to contact me ([email protected]).