Are pulex more seasonal than magna?

So Molch got a bag full of beautiful healthy-looking hopping D. pulex in the mail , set them up the way she has always successfully set up her Daphnia cultures - 20 ga tank, old but clean aquarium water, 60F, sponge filter on slow bubble, some hornwort, a strip light 12 hrs a day, feeding with spirulina and soy protein powder, pH 7.6, medium hardness - and one by one over the next few days they curled up their little toes and died.

Why ??

I can't figure out what I did wrong. This setup has worked well for me in the past for magna or pulex; I have always been able to start cultures and keep them alive for months, until I no longer needed them or started neglecting them and let them crash.

I have several hypotheses about what went wrong this time; does anyone have any insight?

1) maybe water parameters where they came from were radically different and the adjustment was too great
2) They are very seasonal and were ready to pack it in for the season anyways, and did so as soon as they hit the cooler waters at Molch's home
3) My spirulina powder is poisened (?) or has gone bad (doubtful; it's 6 mo old and in the freezer)
4) Daphnia suck
5) I suck.

I collected the sludge from the tank and put it in new water in hopes there's some ephippia in there.

Anyone have an idea what I did wrong this time?

Anything different about the aquarium water you used? From a different tank that had higher nitrates or something like that? That's the only thing that comes to mind (and I would certainly rule out possibilities #4 and #5!!!)

In my experience, D. magna is more sensitive to temperature (both high and low) compared to pulex.

hm, I don't think so. The aquarium they went in was an established tank that housed some hornwort which was healthy and growin nicely. Same water I use everywhere, including previous Daphnia cultures.

After they died, I tested the water and it was ammonia 0, ntrite 0 and nitrate 20ppm. I attribute the nitrate to the uneaten Daphnia food. But I had Daphnia do just fine in higher nitrate than that before, so I doubt that killed them off....

I now ordered some D.magna ephippia from Sachs - maybe I'll have more luck starting a culture from scratch.

I used to have a good working relationship with Daphnia, and now we are in divorce proceedings and barely speaking...

I think hypothesis #5 is becoming more likely

Molch said:

a strip light 12 hrs a day

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Is there any particular reason for 12 hours? I would have thought that a summer photoperiod would be most appropriate to avoid seasonal effects.

Nr 4....But then again I never did understand why ppl culture things like this for anything else than pure interest in Daphnia. I feel the same way about artemia btw I just wish we had a cheap supplier of blackworms here in the uk. But then again what is wrong with frozen foods, larvae are pigs after all, real porkers:artist:

Nr 4... Why are you guys culturing Daphnia btw?

I'm going to consider culturing daphnia if I end up with quite a few newt eggs this spring, I think it will work out much cheaper than buying bags of them as I'm doing at the moment.
Luckily my grandad used to culture them, so I should be able to get them set up

Pulex has a faster life cycle than magna in my experience. Additionally I find the pulex complex is extremely sensitive to oxygen saturation compared to magna.
In my experience magna are more tolerant of low temperatures, where pulex seem to need 70F or higher. For my D. pulex complex cultures I actually use a tank heater set for 72F for maximum yield (on my indoor cultures) whereas I keep my D. magna complex cultures at a constant 60F.

Jesper said:

Nr 4....But then again I never did understand why ppl culture things like this for anything else than pure interest in Daphnia. I feel the same way about artemia btw I just wish we had a cheap supplier of blackworms here in the uk. But then again what is wrong with frozen foods, larvae are pigs after all, real porkers:artist:

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Many larvae require live food early on to trigger feeding response and must be "trained" to eat non-living foods. Additionally the United States does not have a large small animal keeping population, so getting live foods are difficult for many of us not in urban areas (or in Molch's case the largest landlocked island in the world...). European countries in particular have a better demographic of small exotics pet keepers, thus a better selection of supplies is often more available than in most of North America.


As a result of living in the Dog and Cat capital of the world and primarily less than helpful pet suppliers, many of us have no choice but to become experts in breeding live foods to keep exotic pets well fed and healthy.

Additionally, keep in mind that our winter season is in effect, which makes getting supplies even by mail difficult due to extreme low temperatures for those of us in the severe winter zones. (We don't have nice warm ocean currents to temper our climate in places like Nebraska and Alaska...)

Molch said:

So Molch got a bag full of beautiful healthy-looking hopping D. pulex in the mail , set them up the way she has always successfully set up her Daphnia cultures - 20 ga tank, old but clean aquarium water, 60F, sponge filter on slow bubble, some hornwort, a strip light 12 hrs a day, feeding with spirulina and soy protein powder, pH 7.6, medium hardness - and one by one over the next few days they curled up their little toes and died.

Why ??

I can't figure out what I did wrong. This setup has worked well for me in the past for magna or pulex; I have always been able to start cultures and keep them alive for months, until I no longer needed them or started neglecting them and let them crash.

I have several hypotheses about what went wrong this time; does anyone have any insight?

1) maybe water parameters where they came from were radically different and the adjustment was too great
2) They are very seasonal and were ready to pack it in for the season anyways, and did so as soon as they hit the cooler waters at Molch's home
3) My spirulina powder is poisened (?) or has gone bad (doubtful; it's 6 mo old and in the freezer)
4) Daphnia suck
5) I suck.

I collected the sludge from the tank and put it in new water in hopes there's some ephippia in there.

Anyone have an idea what I did wrong this time?

Click to expand...

Molch, looking at the weather up there, I suspect your shipment may have succumbed to drastic temperature shifts during shipping, which will crash any daphnia. That or they filled your order from the "old" tank.

If it were me, I would carefully drain off all but an inch of the water. I would then let the rest evaporate. Once the leftovers are moist but not dry, i would refill the culture with a dose of old, warm tank water and set a heater to 70. Dollars to donuts they will self start from eppiphia after a wek or two of the old evaporation/aestivation treatment.

Jesper said:

Nr 4... Why are you guys culturing Daphnia btw?

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For me- because it's easy, (almost) free, saves me a 5 mile round-trip to a tropical fish shop, and means I always have food available.

I didn't buy any food for my larvae at all this year, just used my two outdoor Daphnia cultures. There was enough produced to feed quite a few of my adult newts as well. They also produce Gammarus, Asellus, bloodworm, tubifex and (don't tell the wife) mosquito larvae that are very useful too.

I am a recent convert to Daphnia culture though, mainly because I've never been able to get an indoor one to work.

SludgeMunkey said:

Molch, looking at the weather up there, I suspect your shipment may have succumbed to drastic temperature shifts during shipping, which will crash any daphnia. That or they filled your order from the "old" tank.

If it were me, I would carefully drain off all but an inch of the water. I would then let the rest evaporate. Once the leftovers are moist but not dry, i would refill the culture with a dose of old, warm tank water and set a heater to 70. Dollars to donuts they will self start from eppiphia after a wek or two of the old evaporation/aestivation treatment.

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well, they did arrive alive and well, and then started dying when I kept them at 60 F. One odd thing about the ones they sent me was that they all appeared to be large-sized (for pulex) adults, with no young ones or different size ranges at all.

I'll try the drying out - refilling method. Maybe they'll come back.

Interesting you would say pulex are more sensitive to cold. Could that be dependent on the strain? I've heard/read the opposite as well. I did keep a pules culture once quite happily at 60 F....

I also want to try to collect some pond sludge locally to see if maybe some Daphnia hatch out if I let it thaw out. Trouble is, I'm gonna need to do hard labor with a pickaxe to get through the ice all the way down to the pond bottom...

meanwhile, I also got some magna from Bill Yanonne, so here we go again..., Daphnia round two

Molch said:

well, they did arrive alive and well, and then started dying when I kept them at 60 F. One odd thing about the ones they sent me was that they all appeared to be large-sized (for pulex) adults, with no young ones or different size ranges at all.

I'll try the drying out - refilling method. Maybe they'll come back.

Interesting you would say pulex are more sensitive to cold. Could that be dependent on the strain? I've heard/read the opposite as well. I did keep a pules culture once quite happily at 60 F....

I also want to try to collect some pond sludge locally to see if maybe some Daphnia hatch out if I let it thaw out. Trouble is, I'm gonna need to do hard labor with a pickaxe to get through the ice all the way down to the pond bottom...

meanwhile, I also got some magna from Bill Yanonne, so here we go again..., Daphnia round two

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It could be. Odds are they are not really even pulex. I suspect the temperature sensitivities I see are due to the effect on oxygen saturation. Low O2 and a low temperature cause most of the pulex complex to die off after eppiphia. Judging by what you say though, I bet this was a case of you got your order filled out of an older culture.

This time of year, I do not order from my regular supplier at Dallas Discus, as they do all outdoor cultures, and the weather down their tends to crash out their cultures. (Wintertime I use Sachs Aquaculture Systems out of Florida.)

SludgeMunkey said:

Many larvae require live food early on to trigger feeding response and must be "trained" to eat non-living foods.

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Yeah I suppose wiggling small pieces of food in front of larvae is a bit time consuming, but I have managed to get most species(I have not kept that hard species I suppose} to start eating on frozen and when that hasnt worked I have gone down to the nearest water body and got me some assorted copepods, it is slightly impractical in below zero degrees but I always seemed to get some kind of tiny animals to feed larvae with... assuming you can get through the ice. I also keep forgetting that not all ppl have a distinct lack of a garden like me... I found daphnia to be horrible, needy indoor creatures, kept copepods alive much longer than daphnia.

SludgeMunkey said:

Additionally the United States does not have a large small animal keeping population, so getting live foods are difficult for many of us not in urban areas (or in Molch's case the largest landlocked island in the world...). European countries in particular have a better demographic of small exotics pet keepers, thus a better selection of supplies is often more available than in most of North America.

As a result of living in the Dog and Cat capital of the world and primarily less than helpful pet suppliers, many of us have no choice but to become experts in breeding live foods to keep exotic pets well fed and healthy.

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Fist of all paris is the dog capital of the world, they even have specialised mopeds that pick up dog poo, 3 ton of dog poo per day in paris alone is what I heard... A few years back the urban dog poo stink in summer was a major problem in France.

Secondly the problem you are describing exists all over europe, maybe less so in the more populated spots and where the hobby is big(uk, germany, netherlands etc}. I never even heard of livefoods in pet shops back in Sweden, I had to hunt for frozen fish foods. Angling worms or dig yourself was pretty much it. I started scouring ponds after reading about copepods here 9 years ago. Before that it was bits of thawed bloodworms, very chopped worms or death for larvae.

Remember that we have loads of different languages here in europe and communication between countries was virtually unthinkable back in the day. I remember the amazement when I realised that Gunther would actually send newts across borders in europe. The western european nations have made war amongst each other for more than a millennium, ever since Charles the fat died... So I feel that it is rather early to see us as one unit even though we do our best to pose:frog:.

SludgeMunkey said:

Additionally, keep in mind that our winter season is in effect, which makes getting supplies even by mail difficult due to extreme low temperatures for those of us in the severe winter zones. (We don't have nice warm ocean currents to temper our climate in places like Nebraska and Alaska...)

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Hmm, I am swedish....

Sorry for being OT as usual..

With great amusement, greetings from "Europe"