[kivyee]

I started culturing Daphnia over the summer and thought I'd share some of my learnings. My current "crop" is IMO in great shape, a nice bright red in addition to being big and juicy

The Journey

I got my starter culture from Canadian aquatics (Thanks Pat!)
Did the usual airline (not airstone for aeration, fed a yeast, green peas etc mix - grew pretty quick...did water changes as recommended and generally felt like it was quite a bit of work. Daphnia were pale/whitish. I proceeded to put them in a big 30 gal garbage bin. Unfortunately my stored rain water had something the daphnias didn't like - lost the entire culture. Thankfully I read online that sometimes eggs survive in the adults, so I harvested all the dead daphnias I could, but them in a 1 gal container w old tank water, and sure enough 4 days later I started seeing baby daphnia in the container!

A little wiser now I nursed the culture back and this time split it into 2, starting a new 5 gal pail.
I decided to do an experiment...I decided to test out some of the information I came across in my daphnia research, namely "add organics and leave them be"...I.e. no aeration and minimal feeding. I added whatever filter gunk, mulm, what have you to the 1 gal container and left the daphnia to their own devices...Only feeding green water twice a week. The 5 gal I kept aerated and alternated feeding green water / yeast mix.
Pretty soon the "lo tech" container started turning green w algae on the sides and with the water turning cloudy. Daphnia were turning red and looked bigger. Density was lower than the 5 gal but I'm on with that. Currently the 5 gal has been converted into a 20 gal styro bin "lo tech" setup. Daphnia was still much paler here...I'm hoping to recreate conditions in the 1 gal.

Learnings

1. More does not equal better. Daphnia really don't need aeration, fancy food mixes or water changes to keep going. You give up density, but you also remove the 2-3 month cycle of crashing.
2. It's better to over harvest them than to let the daphnia get too numerous. Too many = crash...
3. Daphnias like dirty water. Murky water filled w organics = feast for daphnias. My current 1 gal looks like pea soup. I harvest by sucking them up with a turkey baster and straining them out with stockings stretch over a frame. A quick wash with tank water and into the tank it goes.
4. It's awesome to feed live food that can survive and not dirty the tank until they are eaten...Not that they survive all that long in my tank, but when you see the tank water swirling with food instead of feeling trepidation it's now joy

Current set up

I moved my cultures into the garage when the weather started getting cold. I'm hoping it will keep them warm enough to keep going through winter...But I do have a spare heater I might put in. They have a small desk lamp that's on 12hrs a day. The 20gal also has other goodies growing like nematodes and mosquito larvae.

The daphnia has gone beyond fish food to a fun secondary hobby. I enjoy monitoring them and harvesting them

...My wife thinks I've gone over the deep end every time she sees the light in the corner of the garage...

Without further ado...Pics...

 

[josephl]

Very informative thank you

 

[hp10BII]

Thanks for posting your daphnia experience. My cultures crashed so I`m taking a breather before starting a fresh batch.

 

[barvinok]

Nice write-up.
I had somewhat similar experience on a smaller scale. Had 5 gallon pail outside year around for the number of years. It had pine needles, fall leaves, rain water and nice fat daphnia. Sadly someone mistakenly dump that " dirty water".
Now restarting again

 

[kivyee]

Btw wanted to add that I also out the following in the cultures :
1. Crushed dried eggshells
2. Rotting wood for cellulose
3. Straw as "feed"...Need to get more
4. Soil

The idea is having a sustained culture that I just have to add organic material to periodically and make up water.

And if anyone wants that styrofoam cooler boxes (with tight fitting lids) that I'm using for my 20gal "pond" let me know...I have tons of them. Free for BCaquaria members. Dimensions are 47.5 x 77 x 28 cm (including lid) ~18.5 x 30.5 x 11" on the outside. Walls are about 3.6cm thick.

 

[Redshrimp2709]

Thanks for the sample of daphnia. So far they are alive in a small fish down above my 90 gal where it gets close and direct flourescent lighting. I too put mulm and scraps of moss in there. *cross fingers* I think most of them are alive and I still see smaller babies. I do think some died off though. Have you been putting egg shells in for your later attempts?

Drew

 

[kivyee]

I added eggs shells about a month and a half ago. Are you feeding them? If you are using yeast make sure you don't overfeed!

My 20 gal container has lots of scrap moss and aquarium plant trimmings - and they do incredible in there...but I think it actually takes away too much of the nutrients that feed the algae/bacteria. Next experiment is to remove the plants and see if I can get the 20gal to the same state as the 1gal.

 

[hp10BII]

Just adding my experience with culturing daphnia. They were so easy to cultivate when I was a kid, but I had problems keeping them alive for more than a week when I tried to cultivate larger amounts now.

This time I approached it differently. I may have had unstable water conditions in the past, either crashing pH or ammonia/nitrite issues. I bought some cultures from Pat and I divided them into 3 different growing mediums. I used 2 x 4 gallon Sterlite storage containers with crushed aragonite (Caribsea) and a few pieces of matured Seachem Matrix biomedia. I like the Sterlite containers, nice big surface area and a little stream of air from just an airline. Caribsea aragonite is a staple in my Tanganykian and goldfish tanks. It's much more effective than ordinary crushed coral and buffers the water to prevent pH crashes and adds minerals to the water. For fun, I grabbed a handful of potting soil and some crushed aragonite (Caribsea) with a few pieces of bio media in a 2 gallon fish bowl, water filled up about halfway, but without an airline.

The biomedia and aragonite seem to help, the cultures started growing. I fed them with yeast, paprika and powered spirulina every other day when the water is clear from the previous feed. The goldfish bowl daphnia would get a squirt of the yeast mixture from an eye dropper. What I found interesting was that the density of the daphnia in the goldfish bowl was at least 3 times more than the Sterlite containers, and that's with a smaller surface area and no aeration. The difference is the potting soil.

I don't recommend a goldfish bowl - it's too hard to cultivate daphnia with such a small opening. For my cultures now, it's a handful of potting soil, crushed aragonite and some mature biomedia with old/aged tank water. No dechlor with new water - apparently toxic to daphnia. It does produce a high yield, so the cultures will eventually crash. You can prolong the culture with frequent harvesting and water changes, and I like to keep several going as a backup.