Daphnia

[mroli123]

Hi, I recently have had some axolotl eggs hatch and have been buying daphnia to feed them on, which is proving to be a bit expensive, so I am going to try and keep a steady supply going - what I have done so far is, bought 14 packs of daphnia collected some rain water and old tank water from my axoltl tank put it in a bucket and added the daphnia, I have also set up 3 seperate containers which I have put less daphnia in but the same water

I have also added some cooked carrots (which my red cherry shrimp have left) and some snails also from my axolotl tank

I am not sure if this is going to work or not, but hopefully it will allow the daphnia to breed and give me a steady supply of food!?

I live in UK and it is freezing at the moment, I don't know if temp makes a difference?!

 

[Nathan]

Temperature does make a difference, as does the source of the daphnia. Some strains breed readily in cold water, others don't. Are all your containers outdoors? I suggest you bring some of them inside and see if there is a noticeable difference in production. I also suggest you add some vegetation to help keep nitrogenous waste down.

You've got the right idea using multiple containers. Daphnia colonies have a way of crashing without warning.

Remember that how nutritious the daphnia are depends on how nutritious their diet is. If you include a high-quality fish food in their diet they will be better for your axies.

 

[twistedfisher]

I culture daphnia with microfex worms and it seems to create a stable relationship.

I do also add dissolved active yeast to the containers to boost the daphnia population since i have a few killi fish that only eat daphnia since they are spoiled little brats.

Here is an excerpt from an ebook i wrote regarding daphnia and the culturing there of:
Daphnia and moina are one in the same just moina are the dwarfs of them. For this reason I shall refer to them both as Daphnia for the purposes of this chapter. Daphnia can be cultured in a container as small as a 1 gallon jar or in a swimming pool of 10,000 gallons. The principals are all the same when culturing them and as long as you follow the principals you should not have many problems. Daphnia are filter feeders and filter primarily algae from the water along with bacteria and protozoa. The only recommended starting culture I will advise is to get one from another hobbyist or from an online seller. Wild caught Daphnia are potentially harmful to your fish by bringing in possible disease or parasites in the process of catching them in local ponds or streams.
Now that you have you Daphnia culture and your container to grow them in there are just a few things we will need to set it up:

• Old tank water
• Rigid air tubing
• An air pump
• An air control valve
• A stable place to put the container

I am currently using three 10 gallon tanks for daphnia culturing as I have found it is easier to maintain the water quality in it then in smaller containers. Take your container and fill it with your old tank water. Then place the rigid air line into the tank and adjust the air flow until you have about 1 bubble per second coming outta the end of the open air tube. Do not use an air stone since the small air bubbles can get in between the carapace of the daphnia and cause it to break and the daphnia will die. After you add the daphnia you have the set up to grow them. No light is needed nor is a current through the container. Some people report that using black colored containers to help with higher yields but I have noticed no difference from a regular old fish tank. Once again the container you pick is yours to choose and you will find what works for you. There is no cut and dried “perfect” container, only many different options and even more yet to be discovered. I have heard of hobbyists culturing daphnia in a container as small as a half gallon canning jar and others that have swimming pools full of them. Your culture size will be dependant on the amount that you need to feed your fish and can grow or shrink as time goes by.
Now that the culturing container is sat up and we have added our daphnia we need to go about feeding them. This brings a hot topic for discussion among hobbyists everywhere that culture daphnia. I will cover a few of the most popular ways of feeding your culture and I will leave it to you on how you go about feeding them.

1. Adding enough Greenwater to make the container turn a slight green tint. Then add Greenwater daily or every other day as needed or when you can see through it. Greenwater is only one of the possible feeds for Daphnia and Moina. Care should be exercised with greenwater and you can choke your daphnia with too much of it.
2. Another is to put half a bag of frozen peas in the blender with 2 cups of water and a few pinches of high quality flake food and let it run on high speed for about 15 minutes until everything it’s a thick pea soup. Then strain this through a tee shirt and what goes through is a highly concentrated Daphnia food that can be kept in the refrigerator for a week. When it starts to smell rancid its time to make more. Only feed enough to tint the water in the culturing container a slight green.
3. Yet another is to feed them activated dry yeast but this has a faster rate of fouling the water and has to be done with great care as to not cause a tank crash. The yeast should be mixed with old tank water and only a tiny pinch of yeast should be added to it to make the tank slightly cloudy. You should be able to see through the tank with moderate difficulty when there is enough yeast mix in the tank with them.
4. And the final way that I am going to cover in this article is to put them in with Microfex worms. The daphnia will filter out the Microfex Worms waste making the water quality better for the worms and in turn feed the daphnia. This is referred to as a symbiotic relationship in nature and is the safest way to feed daphnia in my opinion.

Harvesting the daphnia can easily be done with a brine shrimp net or old panty hose stretched over a coat hanger. To get the daphnia to gather put a light over your culturing container and wait about 5 minites for the daphnia to come to the surface. Just make sure to never harvest them all and you should not have any problems keeping them going.
There are a few problems that can occur with a daphnia culture and most are with the water quality or over feeding. I cannot stress enough that its better to feed to little rather then too much. Over feeding anything will reduce the water quality that it lives in and in turn make it become toxic much quicker then if proper amounts are used. The best indicator of a reduction in water quality is when you start to notice little black dots inside your daphnia. These are not tumors as they were once thought to be but rather they are ephippium or a resting egg. These eggs have a thicker than normal shell and are the daphnias method to overcome winter, and summer drought conditions when water quality naturally goes down in the wild. These eggs should not be discarded and will hatch when water quality goes back up from a large water change or when the temperature increases again.
Maintaining a culture is not an overly time consuming task nor should it be intimidating. Water changes can be a bit tricky since the daphnia are easily sucked up by any hose that you would use to siphon the water out of the culturing container. A simple way around this is to do what is referred to as an air stone siphon. This is done by inserting an air stone into a piece of air line and putting it into the culturing container and starting a siphon through the air line and allowing it to drip into a collection container. Although this method is a slow process it insures that your daphnia are not sucked up in the siphoning of the water from the culturing container. It is often easiest to do this slow siphon over night or to start it in the morning and then refilling the culturing container later in the day after the siphon has removed a good amount of water from it.

 

[mroli123]

I haven't put them outside yet, its snowing and freezing so I have them in my spare room but that still isn't the warmest place!

Thanks for the feedback, good to see i am along the right lines - I plan to get some floating plants to put in with them, do you have any idea how often to put fish flakes in (I think they feed off of the bacteria and stuff that builds up on the fish flakes not the actual flakes - but I may be wrong!)

How quickly do they reproduce?

 

[Nathan]

They will feed on any small particles in the water- whether living cells like bacteria, yeast, or single-celled algae, or non-living matter like finely crushed fish food. It's better to add a small amount of food every day than a large amount at longer intervals. Females will bear young two or three times a week, and the young ones reach maturity in about a week.

 

[caleb]

There's an excellent article on this very site about culturing Daphnia:

Daphnia

They will only eat food suspended in the water, and can only take in particles less than about 50 micrometres across (one twentieth of a millimetre), so crushed fish food is not likely to be an efficient way to feed them.

I personally use a mixture of spirulina powder, gram flour and yeast, shaken up in a small amount of water- I add this to the culture until the water is slightly cloudy. They'll usually clear it overnight.

I've had to bring my two outdoor cultures indoors, as I was worried they'd freeze right to the bottom (they each had about 15cm of ice). The one that was started with locally caught Daphnia still has quite a few swimming about, but the one started with aquarium-shop daphnia has none at all. Hopefully it'll restart in the spring...

 

[mroli123]

Thanks for all of your help! I haven't got an air source in with them, I was hoping it wouldn't need to be done, but maybe it will!