Post by rainbowfish on Mar 5, 2018 18:46:51 GMT -6
On one of the Facebook pages someone mentioned using “forced hatching” methods of the killifish crowd. I thought I might elaborate upon that a bit further for those of you that are unfamiliar with the methods. Since they didn’t say which method or methods were used I’ll go over 4 methods that have worked for me and more importantly worked when I’ve had stubborn rainbowfish eggs, especially the Pseudomugils. I really didn’t look to see if anyone has been able to explain this scientifically, I’ve seen carbon dioxide, pH, osmotic pressure, feeding stimulation etc. all used as a reason for why the various methods work. I would suggest to you that you might practice on some of your own eggs before you get something precious that you just have to hatch.
1) Micro-worms - Don’t ask me how it works, I followed what was set down by others and it worked for my killifish, and later for my rainbowfish eggs, especially the Pseudomugils. Place the eggs in a very shallow container, and cover the eggs with about 1/2 cm of water, dechlorinated of course, tank water is fine for this. Then remove a small amount of micro-worms from a very healthy culture. Wipe them off the sides of the culture, don’t bring any of that baby food junk etc. into the hatching tray. It really doesn’t take many worms, maybe 10 or so per egg. Is it feeding response, digestion of the egg sac, I don’t know, but it does work for a certain percentage of the eggs, if they were really ready to hatch. After 5-6 hours though I’d remove any extra worms and change the water in the hatching tray. You can wait another day or move on to the next forced hatched method.
2) Carbon dioxide or just a lower pH, I’m not sure what does it but get a piece of airline tubing and start blowing bubbles into your tray of eggs. If you want to check on exactly how long it will take your water to change pH take a like amount of water, and add a few drops bromothymol blue (your basic pH indicator that you buy at the pet store) to a few drops of the water that you’ve started saturating with CO2. It should be a nice blue or aquar marine color or darker when you start. Depending on the hardness of your water (KH) it could take less than a minute to several minutes. If you’re over 400 ppm GH, probably with a KH to match you’re not going to get anywhere fast. If your water is that hard though that’s probably the reason your eggs aren’t hatching (cyanodorsalis excluded, of course). Then go back and do a little heavy breathing into your batch of eggs. It that doesn’t pop them in an hour change the water and try another method.
3) Jiggles - put your eggs in a vial and take them to work, to the grocery etc. Only fill the vial about 1/2 way so that there will be air in the vial in case some fry hatch and you have a ways to go before you get home. Don’t try this while jogging.
4) Pressure - glass vials are better for this. Fill the vial with your eggs and water. You want to make sure that the vial will sink. Drop it into your 55, 110, 200 gallon tank, whatever is deeper. The lid is on loosely so that the pressure increase will transfer to the eggs. I didn’t use this technique very often so I’m not as familiar with it. I’ve had eggs hatch in a couple of hours using this method. I’ve also ended up with fry that have had twisted backs from this method. Was it the method that twisted their backs or was it because they spent too darn much time in the shell and now have problems, I don’t know. I try to use this as a method of last resort.
If all else fails then you probably need to incubate them a bit longer.
Also make sure to read the thread: “Hatching Pseudomugil Eggs – Revised Thinking Equals Success” also on this forum. That article I think if you follow it closely you won't have to be worrying as much about forcing Pseudomugil eggs.