Brine shrimp having difficulty molting

Joined: September 6th, 2011, 2:44 am

July 28th, 2018, 5:17 am #1

I've been trying to raise healthy brine shrimp for most of this year, but each attempt ends just before their baby head fins should be dropping off.
It's around this adolescent stage where they quickly become lethargic and perish within a day or two. I've done experimenting with different salinities, different pH levels, different waters, different lights, adding calcium supplements... nothing has helped so far.
Anyone know why this might be happening and what can be done to fix it?

Thank you.
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notostracan
Triops Newberryi
notostracan
Triops Newberryi
Joined: June 16th, 2016, 9:06 pm

July 31st, 2018, 1:48 am #2

Any more information on your set-up? :)

What salinity/temperature do you using at the moment, any air pump? Lighting strength and timing?

Also what are you feeding and at what stages?

One more thing, mainly out of curiosity, as it shouldn't make much difference, but which strain are you growing?
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Joined: September 6th, 2011, 2:44 am

August 1st, 2018, 6:17 am #3

Earlier in the year I had them in a 1 gallon with a central underground air pump and a clip-on reading light, just bright enough to leave no shadows in the tank. No heater. The temperature in the shrimp room is pretty consistently about 72 degrees Fahrenheit. I fed them packaged sea monkey and sea dragon food, using my old sea monkey spoon. First feeding 3 days after hatching, and then once a week from that point. I don't remember the exact salt to water ratio I used.

Right now I have them in a half gallon, no artificial light, just the sunlight coming in from the other side of the small room. No air pump this time, I think I may have been over oxygenating the tank before so I'm a little wary. I do have a few marimo moss balls living in the tank with one producing a little of its own oxygen, however. No heater still. The temp in the room is higher than usual due to it being summer, about 80 degrees Fahrenheit in the shrimp room. I am now feeding them human-grade spirulina powder, 3 days after they hatch and every 7 or more days after that, depending on how clear the water is since the last feeding. Using the same spoon. Now the salinity is 1 tablespoon to every cup of water.

I believe I have Artemia franciscana! See pictured the last batch that almost made it (I only put a light on the tank for the photo).
20180731_231735.jpg
Last edited by MrFishieHat on August 1st, 2018, 6:21 am, edited 1 time in total.
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notostracan
Triops Newberryi
notostracan
Triops Newberryi
Joined: June 16th, 2016, 9:06 pm

August 4th, 2018, 8:13 pm #4

To be honest I doubt any clip-on reading light could provide a useful amount of light, so the first time I think lack of light would have been the main issue.

Sunlight is good for growing brine shrimp, too much direct sunlight can be an issue as I discovered (algae grows on their exoskeleton and interferes with shedding), but from your description it's hard to tell how much light they are actually getting in this set-up :ermm: .

Definitely remove the marimo ball ASAP! Unlike you may have read elsewhere, it is in no way compatible with brine shrimp tanks. Brine shrimp prefer water that is of sea water salinity or greater for best growth, this will kill marimo. The clue is in the name, brine=water saltier than seawater, so brineshrimp do best in brine :thumbup: . All of the studies I have read conclude that seawater salinity (35ppt) is generally the best for Artemia franciscana, though a higher salinity than this can be beneficial in some ways and may be better for some other species/strains. The instant pet kits (Sea-Monkeys, Aqua Dragons etc.) and hatching kits/instructions for feeding fish will use a lower salinity than seawater, as this gives a better hatch rate, but is much worse for long-term survival and growth. Marimo "moss balls" are actually comprised of a species of algae called Aegagropila linnaei, this species is sometimes found in brackish conditions (salty, but much less salty than seawater) in the wild, but is far more often found in pure freshwater where it does best. So basically, if the salinity is high enough for your brine shrimp to be growing healthily, then it will be too high for the marimo, which will die and slowly pollute the water, and if the salinity is low enough for the marimo not to die, then it isn't salty enough for healthy long-term growth of Artemia franciscana.

Temperature and feeding regime sound fine, spirulina is a good food too, although I much prefer Aqua Dragon food if you still have any left (Hobby Mikrozell is great too, but expensive). Also I don't think an air pump is essential unless you want to grow very high population densities of shrimp, but if you use one on a low power it can only help.

So essentially, I think you need to make sure the salinity is at least 35ppt and also remove the marimo, hope this helps :) . An aquarium LED or low-wattage florescent light source probably couldn't hurt either, depending on how much sunlight the tank already revives. Algae growth is very important for healthy shrimp IMO.
Last edited by notostracan on August 4th, 2018, 8:18 pm, edited 2 times in total.
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Joined: September 6th, 2011, 2:44 am

August 7th, 2018, 7:33 am #5

Thanks so much for the detailed response!
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