What do you mean strip the females holding eggs? Does this mean segregate them from the others? Or do you mean strip them of their eggs?
When I say strip the females of the eggs, I'm talking about removing the eggs from their mouths. Simply net one out that is holding, grab her in one hand the way you would hold a bluegill when removing a hook, then use your other hand to open her mouth, and then dunk her head in and out of the water of a small bucket (while still holding mouth open) with about two inches of water in it. The eggs will come flying out in the water. If you want to keep the eggs and try to hatch them, build or buy an egg tumbler. Just keep in mind, most of the ones I see for sale tend to have screens that are too big for tilapia eggs, so you may have to replace those screens. I tumble pretty much all of my eggs. It's important to note that tilapia eggs are extremely prone to fungus, and you can lose an entire tumbler full of eggs in less than 12 hours if just one egg gets fungus and it spreads! I've had it happen many times, and it's a real let down. The truth is, the fish do a way better job at tumbling their own eggs than an artifical tumbler does. To try my best to combat fungus, I place my tumblers in a dedicated hatching aquarium (no fish) with seriously overkill filtration and aeration. Crystal clear, oxygen rich water is a must. Some people treat eggs with methyl blue to reduce fungus risk. I have not, but it might be a good idea.
If the eggs are in their mouth, does that mean they are already fertilized?
The eggs in her mouth should technically be fertilized. However, sometimes a female gets too anxious to collect them, and they don't get fertilized before she grabs them all. They'll carry around dead eggs sometimes for up to a week before they realize they aren't going to hatch. The point is, if they are in her mouth, the opportunity for the male to do his part has passed, fertilized or not.
How can you tell if they are holding eggs? I do have one that is bulging under the mouth and is darker colored in that area than the others.
It sounds like your female is indeed holding. When they are holding, they don't eat, tend to keep their mouth almost entirely closed and have that bulge under the mouth like you describe. Often times the females will get darker colored as well.
Thanks for all of the info weissguy! you may have saved my whole winter experiment in a single post.
No problem. Glad to help!
