Jump to content

Investigating differences in brine shrimp eggs


Recommended Posts

I had been using Coop eggs, but I ran out, looked around and some other promising brands.  I thought I'd share some of my observations and measurements.

First, they seem to hatch about the same.  I use rock salt for a salinity of about 25ppt (1.017 specific gravity @ 77F) and tsp of baking soda per liter, which gets my Ph to  about 8.5.  I use two water bottle hatcheries that hold about 900ml each.  And heat them each with a 5W that's on for 20 minutes out of every hour,  which keeps it around 80F.  I get good hatches in 24 hours.

I took some measurements of the eggs and nauplii:

Coop eggs are an average of 0.28mm in diameter after 24 hours in water.  Brand X is 0.20mm.

Coop nauplii are 0.53mm long and 0.19mm wide, on average.  Brand X is 0.5mm by 0.15mm.

That 0.05 mm reduction in width seems small, but by a very crude estimate, it suggests that the coop nauplii have 70% more volume than brand X.  Brand X nauplii subjectively look much smaller than coop nauplii.  

I know some people say that smaller brine shrimp can be eaten by smaller fry, but the size difference (in terms of how big a mouth you would need) seems not that large.

The biggest difference between the two, though, comes in how they shells (don't) separate from the nauplii.  The Coop eggs, I get very few sinking shells.  But with brand X, I get lots of sinkers and it plugs up the fancy RO-style valves on the bottom of my hatcheries.  It's very annoying. 

In test tubes, I tried increasing salinity to get the sinkers to float, but it was no use.  I went as high 44ppt (1.031 SG) salinity and they still sank. 😞



Edited by memorywrangler
added the photo.
  • Like 2
  • Thanks 1
  • Love 1
Link to comment
Share on other sites

Love the comparison. Coop eggs are definitely the easiest when it come to shells floating. They are also the chunkiest ones I’ve found. 

The only ones I found that are significantly smaller are from Brine Shrimp Direct. Those are actually small enough I can get fry eating them 4 days to a week sooner than the ACO ones. 

It’s interesting when I start transitioning them to ACO eggs or if I have different size fry. I hatch both in the same Ziss blender. The ACO shells all float and the BSD ones glue themselves to the side and bottom. 

It’s nice to be able to start the fry sooner but my adults don’t even go after the tiny ones. 

Link to comment
Share on other sites

  • 2 weeks later...

Well, I sold off a whole bunch of adolescent platys for a pittance of store credit at my LFS and picked up some San Francisco Bay Brand brine shrimp eggs.  I bought the 6gram vial for $10 -- so $1.60/gram -- which is bonkers (fortunately, the vial is nice...).  They also sell an 80g jar for $24.99 -- $0.30/gram.  For comparison, my BSD eggs are $0.10/gram (for 8oz), and COOP eggs are $0.22/g (for 100g).

Just looking at them, the eggs look very similar to the Brine Shrimp Direct eggs.

I set the new eggs up with my normal recipe, and after 24 hours the results were deeply disappointing -- very low hatch rate so far and it seems like 90% of the eggs sink.  I won't write them off just yet -- I put them back in the hatchery for another 12 hours to see what develops.

Some hatched, though, so I can compare sizes.  They are very similar to the BSD:






BTW, if anyone has some of BSD's San Francisco Strain (https://www.brineshrimpdirect.com/brine-shrimp-eggs/san-francisco-strain-brine-shrimp-eggs/), and wanted to ship me a tablespoon of them (I imagine normal USPS would be fine), I'm happy to do those too.  Right now, however, I have far more brine shrimp eggs than I can reasonably use.

  • Like 1
Link to comment
Share on other sites

On 10/1/2023 at 12:38 AM, memorywrangler said:

BTW, if anyone has some of BSD's San Francisco Strain

I have a large jar of them. Direct message me where I can send them and I will ship you some. 

The ones sold by San Francisco are much bigger than the San Francisco strain. The strain even the eggs are almost a powder consistency 

Link to comment
Share on other sites

  • 1 month later...

@Guppysnail provided me some "San Francisco Strain" eggs (Thanks!) from brine shrimp direct and I've added them to the comparison.




Here's the data:


I apparently didn't gather data for the San Francisco _brand_ eggs.   I found them expensive and hard to hatch.  I estimated volume by computing a the volume of an ellipsoid.  Obviously not a perfect measurement, but it gives some idea of their relative sizes in 3D.

The San Francisco Variety shrimp are a bit shorter but also more variable than the normal BSD shrimp.  The egg size for the SF variety are noticeably more variable.

So, all in all:

  1. COOP eggs are easily the biggest and produce the biggest shrimp.
  2. Normal BSD eggs are more consistent than BSD SF.
  3. BSD SF are more variable, so there are probably some smaller shrimp in there.

For now, I guess I'm sticking with COOP eggs, but I did notice that the BSD SF eggs seem to hatch pretty fast for me, so maybe I'll use them in emergencies.





  • Like 1
  • Love 2
Link to comment
Share on other sites

  • 1 month later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...