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The Goldfish Gazette, Issue #144 Mistake Hatching Brine Shrimp December 23, 2025 |
Goldfish Care TipsA Free Monthly Resource For Goldfish Enthusiasts In This Issue Hatching Brine shrimp to feed to fry should be easy, but what if they don’t hatch in the numbers you expected, even though you've followed the instructions exactly? Mistake Hatching Brine Shrimp
I made a big mistake recently when doing a test hatching of my Brine Shrimp cysts (eggs) before my latest spawn hatched, and it was spectacularly successful.
Unfamiliar Brand and SourceSome years ago, I purchased 500g of Brine Shrimp cysts online of a Chinese brand I was unfamiliar with.The hatches so far have been average, to say the least, and the claimed 24-36 hour hatching time was a joke. I had to extend the hatching time to 48 hours to get anything reasonable from the hatch. I feed fry twice daily, morning and night, so I need reasonable numbers of nauplii in the morning and evening. A 24–36-hour hatch cycle suits this feeding regime. Having to wait for the cysts to start hatching at 36 hours, and finish after 48 meant I had to feed out the nauplii in the morning before I could reseed the container for the next day’s hatch.
The Big MistakeAs my Moors had spawned, I removed the cysts from the freezer and set up one of my smaller hatching containers for a test hatch.After 24 hours, I wasn’t expecting much to have happened as the water temperature was about 26 degrees Celsius (79oF), and it was only 24 hours since seeding, which usually meant only a few hatched nauplii would be floating around. I was completely wrong! The container was pink with hatched nauplii. The hatch was massive. I had never had a hatch this good and this early from this brand. I thought for a moment to consider what I had done differently. Then it occurred to me. When rechecking the amount of salt I should have used, I had inadvertently under-salted the water by half. I had put one tablespoon of salt per liter (quart) instead of two. I checked other brands’ instructions, such as San Francisco Bay, and they all followed the same instructions as the Chinese brand, except that the water temperatures were always below 30 degrees Celsius (86oF). KH - Carbonate HardnessAll the different brand instructions suggest adding a pinch of baking soda (sodium bicarbonate) to the water to increase the pH.This seemed a little vague, as water KH varies considerably. I did some research and found Brine Shrimp prefer a KH of around 10 dKH (179 ppm) or greater. I add 1/8th of a teaspoon (6.25 ml) to two liters (quarts) of water, and that gives a test reading of 18 dKH. The hatch rates don’t seem to have improved since using a precise measure of baking soda, but at least I know if I have a failure, it won’t be that. ConclusionIf you are not getting the hatching results you are expecting, try reducing the salt.As shown above, the instructions are quite clear, but they don’t work. I double-checked again that I hadn’t got the mixture wrong, as this brand specifies the required salinity in ppt (parts per thousand). 35 ppt is the salinity level of seawater. The salinity level I am using is 13 ppt. I can only assume the company packages and distributes the product without having any expert knowledge about it. I should have been suspicious when the instructions stated "Maintain strong illumination throughout hatching period." which is completely unnecessary but is often repeated across websites. Other factors that can affect the hatching success rate are covered in my earlier Goldfish Gazette #078. Let me know if you have had a similar experience with poor hatches and if reducing the salt produces similar results to mine. Happy Festive Season!May you, your family, and your Goldfish have a festive holiday season and a prosperous New Year.Comments? Ideas? Feedback? I'd love to hear from you. Just reply to this e-zine and tell me what you think, or what topics you want to be covered. www.facebook.com/aboutgoldfish |
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