Normally I don't recommend any Africans in anything less than a 55 gal
tank with the exception of shellies. But I think that if you limited the number that you have, you could definately breed. Since labs are so difficult to sex, purchase them as adults if at all possible. That way you are more likely to get 1M and 3F. Either choose to breed the yellow labs or the zebras. (Do you have a scientific name for the Red Zebra?). Stocking a 36 gal
tank will allow you to have about 8 fish. And if you do have fry, then you will need a place for them to inhabit. Decorate the tank with lots of rock work, a few plants, and a sand substrate. Depending on your tank pH and hardness, you may want to add crushed coral to the filter to make the environment as breeder friendly as possible.