One in a hundred?
Yes, in the wild. Under controlled circumstances, as in your aquarium, we are talking about a 99% possible survival rate!
OK, now we are talking big Louisiana fish fry material here eh? You got it!
All it takes is a little "fish diplomacy". When the female is "pregnant", you will see that she is swimming around with her mouth full, and she will not eat.
Mark that day on a calendar, wait 7 days and get her out of there and into the "delivery room". Tilapia, like any other fish, just doesn't like it when you chase after it with a net. Yet you want to get her out of there and into a place where she can comfortably "deliver" the babies.
What to do? well, you have to catch her in a net. You do this by S-L-O-W-L-Y following her around the tank until she zigs when she should have zagged and she ends up in your net. You S-L-O-W-L-Y lift her out of the water and run to your delivery/nursery tank. You release her into the delivery tank and make sure to check the net for eggs/fry she might have released while on the way. Just drop them into the tank, she will pick them up after a while.
That means a clean floor, no sand, gravel or anything else in this aquarium. You also want to wrap the water intake to the filter with a little piece of netting, this will prevent the fry from getting sucked up into it. Sponge filters also work very well for this purpose.
Soon (in a day or two), she will not allow them into her mouth anymore. It is time for her to get back to work. Care must be exercised at this stage. She WILL eat her young if you let her stay in the tank with them too long! I suggest removing her when it is clear that the fry can swim around by themselves.
Carefully catch her in a net and put her back in your big aquarium. Make sure that she gets a few decent meals before the male breeds with her again, remember, she has not eaten in a week!
There, wasn't that easy!
Now all you have to do is take care of the little ones by feeding them finely-ground, high-protein, fish food and by keeping the aquarium clean. They almost double in size the first day so feeding small amounts frequently is best. Don't forget water quality!
When they are fingerlings about 1 inch long you can place them in a larger tank. At this size they can travel well so if you want to sell fingerlings this is the right size. If you want to raise them to market-size you can wait until they reach about 1 ounce (3-4 inches) and place them in a large grow-out tank.
Bigger females in one of the pools outside in the greenhouse. 3 of these females had a combined "litter" of about 800 hybrids on April 21 through 23, 2008.
Notice the "chicken wire" netting around the tank? it prevents them from taking a leap of faith and jumping out of the tank. For some reason they seem to want to go out for a walk without a leash!