I have some very old eggs that just don't hatch. I figured I may as well try them.
Yep. That's what made me try it and my old eggs went from a less than 40% hatch rate to a nearly 100% hatch rate.
How many eggs do you tend to decapsulate at a time? I have probably 10 to 15 grams of old eggs to try this on. Think that will be too many for this setup?
I have done about 3 Tablespoonsful of eggs at a time. You might want to start with a smaller amount at first just in case it doesn't work and you have to perfect your technique. As well, if you don't have a lot of fry to feed, you probably don't want to do too much at a time - they obviously won't stay dormant for ever after decapsulation.
Also...after the hydration, do I pour out the water before adding the bleach or just add bleach to the mix?
Nope, I just add an equal amount of bleach to the water. I use fresh water to hydrate, then add salt and let it dissolve. Then I add the bleach and start stirring.
I have a brine shrimp net. The shells literally dissolve right? I don't have to worry about also filtering out the shells with the eggs?
If you have a brine shrimp net, life will be soooo much easier (can I get one off the site yet? I'd love to have one). Just empty the whole bleach mixture into the net to strain them out, then rinse, rinse, rinse, rinse etc. It will take much less time than what I do with stirring and siphoning off the mixture/water. And yes, the shells completely dissolve so no need to worry about separating them.
Finally: how long do the eggs take to hatch once you go to hatch them, and how much salt would you add to the hatching water if you used a cup of water to hatch in (I usually just toss some random amount of aquarium salt in and maybe 1/4 the time the salinity isn't right for hatching).
I hatch them exactly the same way I hatched them before decapsulating. I use the same saturated brine (just because it's easy to get at) but have used a mixture of about two Tablespoons of salt to approx. 1 Litre of water. The big thing I have found is that if you add Baking soda to the brine to raise the pH they hatch much better. When I don't use the Baking soda I never get good hatch rates (my water has a low pH). I remember reading somewhere that the pH of the brine matters more than anything else. I have been hatching them without light and just sitting on my counter (and the house goes down to 60F at night now that it's winter). After 24 hours of aggitation, I simply filter the whole solution out using coffee filters and a funnel. Since the shells are all dissolved, it doesn't matter whether I only catch live BBS - I can harvest everything in there. All I need to do is separate them from the brine. (I've also been storing the extra hatched BBS in the fridge in regular water for about 12 hours. They still seem to go for them the next morning. Means I only have to do one hatch each day rather than two).
I noticed that the last two hatchings I've done (maybe the last week or so) haven't done well... the decapsulated eggs are at least 2 months old now, so it's possible that they are starting to "die" on me. I'm going to try keeping the light on next time to see if that helps. This will be my last hatch on this batch of eggs anyway - there's only enough left for one more
The nice thing is that even if they don't hatch, the fry can eat them. I find the older fry don't seem to care if they are hatched or not. The younger ones still seem to need the wriggling to stimulate them to eat though.
Note on brine.... As I mentioned, I use the brine from my water softener. I also use the water softener salt rather than aquarium salt for all my fish needs. I buy a big bag of pelleted salt for about $5. I drop a pellet or two (each pellet is about 1 tsp) into the 5 Gallon tanks whenever I think they need salt (ie fin rot, parasites, doing poorly, etc) and it dissolves itself. The fish even seem to like it - I've seen them swim through the bubbles it creates as if they like it. To make a good brine solution, take a container, fill it with water and add enough salt to more than cover the bottom. You will have a saturated brine solution if there is still salt sitting on the bottom of the container. To use the brine, simply decant the brine off the salt into another container. Then you can use the left-over salt to make your next brine solution (although I use mine over and over again... I just add fresh water to it to compensate for evaporation. Once it gets grungy looking I'll toss it and start with new).
