Blue talapia birth control alternative?

[John E Windsor]

I couldn't come up with a better discussion title. Okay, maybe I could have.

I am kicking around the idea of growing out talapia that I can net locally. The lakes here are loaded with what I assume are blue talapia, so we could have an endless supply of fingerlings at no cost. We have an extra 275 gal. IBC tote that I could cut in half to make two 125 gallon fish tanks, plus the 275 gal. IBC fish tank already in our system. I figure 40 to 50 fingerlings in each tank, max. To start off I'd stock the first 125 gal. tank and let the fish grow for several months before stocking the second tank. As the fish in the first tank get larger I could move them into the 275 gal. tank to grow them out.

Now, we could (maybe) try to determine the sex of our talapia and stress them out. That seems to be labor intensive and not an easy task. So, how to stop them from reproducing is the question. I've read that a few gold fish in the tank will take care of the eggs and/or the baby fish. Or a couple of large mouth bass of the same sex will do the same. Another alternative would be a cage inside the tank, or a mesh of some type on the bottom of the tank. Somebody even told us we could simple net the babies off of the top of the water.

Your thoughts?

[TCLynx]

Well it will depend on your goals.

If you simply put mixed sex tilapia in the tank and allow them to breed, you will find that the females don't grow well since when they are holding eggs/fry in their mouth they are not eating and therefore not growing.

This is going to hold true with the following options

1-do nothing and just let them do their thing

2-using predator fish to control population.  Since tilapia are mouth brooders, it is difficult for other fish to eat the eggs since the female picks them up right after they are fertilized.

Best bet to get good growth while controlling population is to use the cage or mesh bottom above the bottom of the tank.  Just remember that any flat surface will provide a chance for them to breed.  A hide or plumbing fitting dropped into the cage can give them an opportunity to breed, you have to make sure the bottom doesn't allow a solid flat surface anywhere or they will breed when temperatures are right.

[John E Windsor]

What materials can I use to build the cage or bottom mesh other than the galvanized hardware cloth?

[TCLynx]

I've done it with polyethylene netting and pvc pipes as the frame and zip ties