Daphnia

[Shetland James]

I've started to breed/culture Daphnia, and I'm looking for some advice.

I got 3 live feed pouches from my local supplier and put them in a spare fishbowl I had lying around with some tank water, some tap water and of course the water they came in. The water is usually cloudy a] because I'm feeding them yeast mix and b] because I haven't really figured out the best way to clean a bowl with Daphnia in it. So far 2 have eggs on their backs, so about 7-8 eggs from what I can make out.

I keep a light on them from about 8 when I get up to 11 when I go to bed, I've heard that more light can help them grow faster.

Anyone got any advice? (keep in mind that I live in the bloody Shetland Islands and at this time of year getting Sunlight is ridiculously hard! )

 

[BillD]

If you are seeing cyst packs forming, they are nearing the end of their cycle. They probably aren't getting enough food or it's too warm, and they are preparing to enter a dipause. Normally, the young are born live, until conditions deteriorate, at which time they start to form cysts. For real success, you need green water, and the greener the better. The bigger the container the better. I have some going in a garbage can right now. In the spring, I grow them on my winter pool cover. The pool cover "pond" produces millions of them.

 

[Shetland James]

They're still living and there are definitely more of them than when I bought them. I'm using a fish bowl and I'm not sure of the best way to clean it without having to shift all the daphnia.

 

[BillD]

I don't clean my containers. The grungier the water the better they do.To have any meaningful numbers you need a larger container.

 

[Shetland James]

You don't clean them? That's quite interesting. How do you maintain water flow - sponge filter? My water was actually OK but there was all this white crap gathering at the bottom which I presume was leftover yeast.

I wish I would have read this because I just cleaned out my tank entirely. Would you recommend getting a small 1/2/3 gal tank and having a heater in it? This daphnia thing I've got going on is just an experiment, really.

 

[BillD]

I would notuse a heater as that could send them into dipause. Warm water is a trigger for some species to enter dipause. Dipause is a dormant state they go into, by producing cysts, for the next season. Any container will work. I usually have a few plastic pails of around 3 gallons with some going. The bigger the better. When my big culture is going in the spring I feed them by the thousands. Daphnia are about 90% water, so you need to feed lots. I keep daphnia in front of the fish 24/7 for several weeks, until I open the swimming pool for the summer.
I do have an airstone in the garbage pail I am using but it isn't normally something I do. my experience has been that they aren't that easy to raise indoors, as providing food is an issue. I have used yeast, but green water is the best thing, and difficult to culture indoors, at least for me.

 

[Shetland James]

See where I live the outside temperature even in the summer must only be about 10 max. We don't get a lot of sunlight!

So I'm not sure that I could keep them anywhere but inside!

Did you get eggs to hatch them with or a live batch?

 

[BillD]

I started my original culture in the spring of 1995, with live daphnia from a pond. my catch was so poor that day, I just dumped the lot into the pool created on the winter cover of my swimming pool. The water was so green it looked like pea soup. the dog had defecated all over the pool during the winter, which created a very rich environment for green water. The 60 or so daphnia took off and in about 3 weeks the water started to clear and there were literally millions of daphnia. They formed brown clouds in the water. I have maintained them every year from that culture.
Your summer temps are ideal for daphnia. The pond I collected the initial culture has no daphnia once the water warms up. They go into dipause until the next spring. I have found that when the water on the pool cover gets warm, the daphnia start to form cysts and they form a ring around the edge of the pool.It is either because of the temperature rise or their food source is running out.
While daphnia may not be as good a food as insect larvae, they still increase growth rate and the fish do like them. Because of the high water content, which is true of all live foods, the fish can consume a lot of them. The hulls provide bulk so it also cleans the fish out. All in all, I think they are a good food and worth the effort.
I didn't realize that Shetland was that far from Scotland. You are very far north.

 

[Shetland James]

So my Daphnia have begun to bloom now. There's quite a lot of little ones in the bowl. Not "loads" but enough for me to definitely notice. This is good!

Water is pretty yeasty but whatever I'm doing seems to work.

 

[Shetland James]

BillD - do you know how long it takes a Daphnia to mature so they can give begin giving birth?

I started out my culture from a live-food back in the store and it only had 2 large enough ones but now there is about 7-9