my ostracods

well, i finaly decided to start a thread about my ostracods. i find them to be an excellent live food for small fish since they stay alive untill eaten, and spend their time eating detritous while they are alive.

about a week ago i emptied my ostracod tub i have outside and harvested all the ostracods. i let the sand at the bottom dry in the sun for a day and refilled it with water. i can already see thousands more that have hatched out. they are a little larger than a newly hatched baby brine shrimp.

here is a pic of how i culture them:

the tub on the right has the ostracods in it. in about a week they will start laying eggs. ill let them go for another ten days or so in order to allow them time to lay eggs, and then i will harvest all of them by pouring the water through a metal coffee filter and restart the whole process. fairy shrimp would also grow in this setup if it was moved indoors where the temps are a lot lower. i get the green water going by adding a squirt of phyto feast to a ten gallon tank and adding a light and aeration to it. when the water turns bright green(in a bout a week) it is ready to start seeding cultures and feeding to my daphnia.

there really isnt much to it. i find that you really cant keep a culture going to long, most of the eggs need to be dried out in order to hatch.
if you time the hatches and harvest out right, you can get nauplii at any stage of their developement. this fact has allowed me to raise nothobranchius species exclusively on ostracods in the past.

anyway, thats about all i can think to include right now. im sure those of you who are interested in this will come up with questions for things i forgot to include.

Auban.

That's really cool. How did you originally collect the ostracods?

they came in a batch of fairy shrimp eggs from arizonafairyshrimp. i isolated them, which was quite easy since they layed eggs. i just made their own little tank and every time i saw one in the fairy shrimp tank i moved it too the smaller tank. i sucked them out of the fairy shrimp tank with a piece of airline tube. that was a few years ago.

just harvested a few, partial harvest. they produced pretty well this time. i think ill let them go for a few more weeks and see how long the production holds up.



i put them in a small tank to feed them and let them set for a couple days. by adding some course sand or some crushed leaves to it, i can get thousands of eggs. within a couple days i they should lay enough eggs to produce about a thousand or so within a week after i dry and rehydrate them. they are very prolific.

it is possible to keep them as sustained cultures. in fact, that is how i used to keep them for years. i do find, however, that they reproduce much faster once the culture is going if i start a dry/wet cycle.


http://s1242.photobu...0714_102607.mp4

this is a video of them doing their thing.

Edited by Auban, 14 July 2012 - 10:01 AM.

It's like an ostracod tornado

I'm terrible at in-tank live food cultures. I actually feed my baby Elassoma gilberti microworms and the adults grindal worms because I can't even culture sea monkeys (artemia/brine shrimp). Whenever I try to get them going continuously I either overfeed them or just look at them too much or something and they all die. I have never been able to sustain a continuous culture of any sort of tiny aquatic life, although I keep trying. *sad face* I do kind of cheat though. I found a vendor on aquabid who sells vials of the dried eggs of rotifers. They are really amazing. You just open a vial and add it to your tank and a few days later there's all this micro life. Have you considered selling your ostracods like that? And can you take us through the continuous culture care instructions? It would be super helpful. I am supposed to be culturing marine rotifers for one of my breeding projects and I have no idea how I'm going to make that work when I can't even keep sea monkeys or freshwater rotifers alive.

i have considered selling them, but i dont know what species they are. they came in with some fairy shrimp i bought several years ago and i have been keeping them ever since. whenever i get around to identifying them, i will be more willing to sell them. i just dont like the idea of selling something if i dont know what it is.

so far as keeping them in continuous culture, its pretty much like keeping a tank full of pond scum. actually, if you can make pond scum in your tank, these guys will love it. they seem to be extremely hardy when it comes to water quality. i even have them slowly reproducing in a couple breeder tanks, so it seems at least some of them are capable of reproducing in th presence of fish. for about a year, i kept a ten gallon ostracod tank that i never cleaned. i just left the lights on 24/7 and fed them every once in a while. i tried out lots of foods, feeding them everything from dandelion tea to finely crushed fish flakes. they reproduced fastest with green water, which will eventually end up in their tank.

eventually i did a large water change and saw their numbers explode. it seems that in continuous culture they will reach a population density that prevents them from producing summer eggs, but if you stimulate a large hatch via water change, they are capable of suviving at the larger numbers. from there they will start laying only winter eggs which have to be dried(or at least exposed to a dramatic drop in osmotic pressure). but hey, thats a lot of eggs... considering that they reach adult sizes in about 3-10 days(temperature controls the growth rate) it isnt hard to culture them in large numbers.

the resting eggs are also very resistant to chemicals. whenever i refill my outdoor culture with water, i just turn the garden hose on and fill it up. no dechlor. the city adds huge amounts of chlorine to the water, and the ostracods still hatch. it just takes them a little longer, they wait till the chlorine is gone.

this is probably the easiest live food i have ever cultured(besides dubias roaches). unlike brine/fairy shrimp, they arent very sensitive to changes, even in their first several hours after hatching, and unlike daphnia, they can eat off the bottom/walls of the tank. if you add food and it settles out of the water, no worries. they will still find it.

I thought of a new question:
How do you go about drying your culture?

The reason I'm asking is I'm looking into champagne yeasts to use for my DIY CO2 bioreactor I'm going to set up in my Elassoma gilberti planted tank. When I used baker's yeast the bioreactor smells like prison wine [terrible] after two weeks. So I was thinking of using a champagne yeast strain to make the waste in the bioreactor not smell completely terrible. But champagne yeast is freakishly expensive. It occurred to me that I am buying it to culture and theoretically once I set my bioreactor up I'll have it growing indefinitely. Should I just take some of the previous batch's foul water and seed the new batch with it? Or is there some fancy way to dry water out to leave spores? Do you let your tanks air dry to dry them out? Or do you like use a hair drier to make the process faster? More information would be appreciated. I know a lot of these vernal pool creatures need dry phases to go through their life cycles. It would probably be useful for cultures of atemia, too.

i dry them out by draining the tank untill the sand is exposed and letting it set untill its dry. not much too it. if i want the process to go faster, i will use a shop light with an incandescant bulb in it. the outdoor culture takes about a day to dry in full sun. indoors, it may take up to three. im not really sure how that would translate to yeast though.,, i have seeded my CO@ reactor with some of the sludge left over before, but i also added more yeast. it seemed to get it started faster if i used a little of the old sludge(yeast) so it makes sense that you could keep reusing it. i would let the whole thing settle after it is done producing CO2 and siphon the stuff off the bottom, or siphon most of the liquid away. you could then pour it onto a pie plate or something and let it set untill its dry. if you are just going to reuse it, i dont think there is a need to actually dry it. the only problem i could see is if you constantly used all of whatever yeast is left. you would eventually end up with a reactor that produces way too fast and quickly burns out. i have had that problem before, which is why i prefer to rinse my bottles out and start with new yeast.

Edited by Auban, 15 July 2012 - 12:30 PM.

Interesting, thank you

i just got a book at a LFS that is right up my alley. Plankton Culture Manual, by Florida Aqua Farms Inc. the book is by far the best one i have ever found about culturing plankton. it has a huge amount of information about culturing plankton, focusing mostly on marine rotifers. it goes into detail about what foods they grow best on, what they eat, how to set up a small scale batch or continuous culture with things like 2 liter soda bottles, etc.

here is a link to their site if anyone is interested.

http://florida-aqua-...t=BOOKS_MANUALS

Edited by Auban, 17 July 2012 - 12:21 PM.

i just got a book at a LFS that is right up my alley. Plankton Culture Manual, by Florida Aqua Farms Inc. the book is by far the best one i have ever found about culturing plankton. it has a huge amount of information about culturing plankton, focusing mostly on marine rotifers. it goes into detail about what foods they grow best on, what they eat, how to set up a small scale batch or continuous culture with things like 2 liter soda bottles, etc.

here is a link to their site if anyone is interested.

http://florida-aqua-...t=BOOKS_MANUALS

Thank you

the part i find most interesting is on the topic of phytoplankton. rotifers vary wildly in nutritional value, which is determined by what they eat. some fish larvae will simply die on rotifers that are fed only yeast but flourish on rotifers fed certain types of algae. hatcheries that buy live rotifers fed on yeast can feed the rotifers on live phyto for a couple of days and that seems to solve the problem completely. it seems rotifers are a perfect food for larvae because their nutritional value can be easily controlled by their diet. i wonder how true this is of ostracods...

the gears are turning in my head. some experimentation is in order.

Edited by Auban, 17 July 2012 - 11:38 PM.

Which powdered algaes have you tried in the past or do you use the lettuce+blender=greenwater method?

i have used chlorella and spirulina powders. i prefer chlorella to spirulina, but both seem to work well. it seems that spirulina powder has larger particles that settle to the bottom quickly, so care must be taken to avoid overfeeding. daphnia only eat out of the water column, so anything that settles on the bottom will only rot and can foul the water. chlorella grows as green water anyway, so it seems to have smaller particles that stay suspended untill they are eaten. live green algae is by far the best way to go for daphnia, however, since it will stay alive untill it is eaten.

both powdered spirulina and chlorella work fine for my ostracods. i think they eat out of the water column as well as detritous, but im not really sure. they dont clear the water, so im assuming they get most of their food from the bottom of the tank.

i do use blended plant leaves often. i put dandelions or aquarium plant clippings into a magic bullet and then strain the pulp out with a metal coffee filter. solid matter goes to my earthworms and liquid goes to my ostracods. dandelions really seem to help the ostracods. they have a sap that causes a lot of the suspended food to precipitate, making it fall to the bottom where the ostracods eat.

i have used chlorella and spirulina powders. i prefer chlorella to spirulina, but both seem to work well...

I also love using chlorella due to its detox property.

Are you still culturing ostracods? I am a biochemist and would like to harvest ostracods for experimentation (protein isolation). Can you provide animals or culture conditions?

my cultures are all dried up right now, but i still have some sand, so ill see if i can get some going again. you can culture them in just about anything, but they seem to do best in hotter water. they can survive temps that will flat out kill daphnids.

my original culture came from "arizona fairy shrimp", just google that and you will see the company come up. anything that they sell that advertises seed shrimp should have the same species.

to be honest with you though, you can probably just scoop up some sand from a dried up pond or creek bed and isolate your own culture of ostracods. i have found them all over the country in nearly every location that is occasionally wet.

Sorry to take so long to reply. Since then, yes, I got Daphnia eggs from "Arizona fairy shrimp" and ostracod eggs come in the pack. Got a small culture going in the lab, but it is enlarging very slowly. Need patience and a lab helper to dip out the ostracods to a ostracod-only tank. Have also done some local collecting but no luck yet. thank for previous comments.

im glad to hear you got some ostracods.

i have just started to restart my ostracods. i tried wetting some of the sand i had before, which i THOUGHT had ostracod eggs in it, but it didnt produce anything. i thought i would have to order more eggs, but as luck would have it, one of my fish tanks still had ostracod cysts in it. i had drained the tank for a few months and planted a few terrestrial plants in it. when i watered it a bit too heavily, i started seeing ostracods swimming around in a shallow pool of water. i fed ostracods to this tank quite a bit, so it makes sense that they laid a few eggs in it.

right now i have a small number in a gallon sized glass jar. in a few weeks ill drain the jar down, let the sand dry, and add water again. their numbers will be much greater next time. im already seeing some small ones swimming around, so i know they are reproducing. that said, the number of ostracods that come from a new hatch is much greater than that which is produced by a sustained live colony. i would guess that one live ostracod might produce ten small ones in a couple weeks while its alive, but it will lay a LOT more eggs than that, in the same two weeks. if even a third of them hatch on the next hydration, then they will reproduce quite a bit faster by constantly drying and re wetting the substrate.

since it only takes a couple days to dry the substrate and re hydrate it, its much faster than trying to go with a continuous culture.
something that i have noticed is that they seem to lay a lot of eggs when the population gets dense. they lay so many eggs that they can be seen all over the place, on a lot of different mediums. you know they are laying eggs if they gather in clusters.


one of the oddest things i have seen concerning ostracods is that they will sometimes gather on live animals. i have seen them gather on fairy shrimp and small fish before. at first, i thought they were eating them, but as i watched, i saw that they ended up just laying a lot of eggs on them. it usually kills the fairy shrimp. i have only ever seen it in very dense cultures.

Edited by Auban, 08 June 2014 - 12:59 AM.

some pics i took of the cysts. they swarm various objects and lay their eggs. first two pics dry, second two wet. some of them hatched without drying.