Rotifers instead of Daphnia

[Corrie]

I think I read every thread and post on this forum before I got up the nerve to join.;)

I noticed that a lot of you guys are using daphnia as a first food.

I have never cultured a daphnia in my life.

I do have years of experience culturing rotifers though.

Have any of you tried rotifers as a first food?

I know with rotifers, you consider them empty sacks.
Like a zip lock bag with nothing in it.
We use them as carriers, and what you feed the rotifers is what
you are feeding the fry.

Would daphnia be that same way?

Sorry if this is an obvious question. I tired to find this out on the internet,
but couldn't seem to find it.

Thanks again
Corrie

[bekko]

Goldfish fry are really big. It would be nice to have rotifers or copepods to start them out on, but they sort of out-grow rotifers in two days. Moina have more tissue and can still be gut loaded.

-steve

[Virginia ranchu]

Hi Corrie,

While these are all good foods, I think that newly hatched brine shrimp are by far the easiest thing to provide in adequate quantity. I supplement with daphnia when they are available, but I find it very labor intensive to keep them going at high density (the daphnia). Also, if you haven't tried the decapsulated brine shrimp eggs, these are inexpensive, and you don't have to hatch them. Very young fry will accept these readily.

Rob

[johnatoranchu]

Hi Corrie
There really is only one food for goldfish fry and that is newly hatched brine shrimp. Easy and reliable to hatch and in the States the eggs are also very cheap - they are three times more expensive in the UK. I usually buy between 24 and 48 1lb tins every time I go to the States. Unfortunately baggage allowances have been halved so I guess I'll have to manage with fewer clothes on future trips!
Feed the fry on brine shrimp until they are about an inch long - it won't take long. The other major benefit of using brine shrimp is that they are generally disease/parasite free whereas when feeding daphnia etc., you run the risk of introducing disease, flukes and/or other parasites. If you add up to 5 grams of cooking salt per litre to the fry tanks the baby shrimp will live until they are eaten, minimising the risk of fouling the water.
Once the fish are an inch long you can feed them on bloodworm, dry food or anything that takes your fancy - the fry will have got off to the best possible start.
John

[Corrie]

I think this might deserve a better/longer answer on my part and the reason I'm thinking along these lines.

I have been breeding clownfish (Nemos) for a little over 15 years now.
Co-culturing the fry is very easy with rots (rotifers).
Feeding brine shrimp (NHB) causes a lot of deformaties and some nerve disorders in clownfish and does not have the right balance of nutrients.

Plus, believe it or not, hatching brine is a major pain!

"but they sort of out-grow rotifers in two days. Moina have more tissue and can still be gut loaded."

Steve, that's what I've been trying to figure out. Size of fry, etc. Clowns grow fast too and most every book you read on them will tell you to wean them over to NHB (newly hatched brine) by seven days. I do not do that. I keep them co-cultured for at least a month or more, until they are a good 3/4 inch. Along with introducing a dry food. I get much faster growth, no deforamties, and no "fright" problems.

It's good to know that moina can be gut loaded. That's the same way you work with rots.

"very labor intensive to keep them going at high density (the daphnia). "

Rob, I would raise them the same way I raise rots now. For me, it's a lot less labor intensive than de-caping brine, sterilizing bottles, setting the bottles up, waiting on the hatch, seiving them, rinsing them, etc etc You would not believe how many rots you need for a few thousand baby clowns. I have the hang of that, no problem.

"if you haven't tried the decapsulated brine shrimp eggs,"

I can tell you how to de-cap them yourself if you want. It's a lot cheaper.
All I use is Clorox and Hypo.

"when feeding daphnia etc., you run the risk of introducing disease, flukes and/or other parasites."

John, this might sound like a dumb question, but why would your let your cultures get contaminated?

I just have no faith in brine shrimp and it really is a pain for me. I hate having to do them. For one thing, you have to buy them.
Once you get a culture started, it's free forever.
Plus, I don't know how fast you can bump a daphnia culture up, but I can double a rot culture in one day. Knowing how to do that when you co-culture means you can keep densities up right along with the fish growing.

I suppose I better start learning something about culturing daphnia, huh? LOL

Rob, you mentioned it's hard to keep a dense daphnia culture going.
Can you tell me about that?
How did you do it?

Thanks guys, I mean it!
Corrie

[bekko]

how fast you can bump a daphnia culture up Moina will double every day in continuous culture if well fed with axenic algae cultures or algae paste. Green water can occasionally get that sort of growth but is much less predictable. When growing them on yeast or manure the doubling time is at least two to three days. Daphnia are somewhat slower.

Once you get them up and running well, Moina can clear 100,000 cells/ml in an hour or so and have to be put on a drip system or fed multiple times each day.

-steve

[johnatoranchu]

Hi Corrie
I am reluctant to write this post on the basis that you certainly know much more that I do on cultivating rotifers and breeding marines but I would like to make an observation on using brine shrimp. I was surprised some years ago to realise that there was a thriving industry in the UK breeding clown fish (with most of their output being exported top the States surprisingly). Newly hatched brine shrimp is/was the main food for fry BUT I was told that the eggs had to come from a marine source as those from Utah and other salt lakes, whilst being excellent for rearing goldfish and other freshwater fish, were no good for marines as they lacked essential nutrients so I wonder if the eggs you used were from Utah as that would explain the nutritional shortfalls you experienced.
Am I right in thinking that the rotifers you produce/use are marine rotifers? I tried freshwater ones a few years back but it was a big and costly mistake - 4 teaspoons of eggs cost more than a 1 lb tin of brine shrimp eggs. Because it is extremely difficult to keep a daphnia culture going, assuming that you want enough to raise several thousand goldfish fry as I do, I deduced that producing freshwater rotifers could be an excellent alternative, envisaging that my money would buy a tin of eggs which I could add to the culture as and when I needed to increase my supplies. It didn't work!
The reason I mentioned disease, parasites and other nasties being introduced with daphnia is that I could/can not envisage daphnia cultures of sufficient size being reared in an artifical indoor environment. If the cultures are outside they can easily become contaminated with glass worms, water boatman etc. which are difficult to detect when they are small but which would enjoy devouring goldfish fry. Most, probably all, the hobbyists here who use daphnia catch it from the wild as that is seen as the only way to have them available in sufficient quantities to feed a hungry hoard of goldfish fry. Also, "in captivity" daphnia reproduce in "blooms" - millions one day - none the next - which is useless from the goldfish breeder's point of view.
Can I please ask you to share your rotifer production techniques with us and if possible use the same techniques on daphnia to see how successful it is - I sense an opportunity to revolutionise our fry growing techniques!!!!!
John

[Virginia ranchu]

Hi Corrie,

I'm impressed that you have been raising clown fish. I too am interested to hear about your rotifer culture techniques. I have experimented with daphnia for several years, and have never been able to produce enough daphnia indoors to rear a spawn of goldfish exclusively on daphnia. I also raise some tropicals, and I could probably produce enough daphnia to feed tropicals. If you have the outdoor space, you might be able to get enough daphnia by culturing in rotating stock tanks started with horse manure and green water. However, unless you live in a warm climate. This all stops in the winter anyway.

For indoor culture, I use a 20H aquarium containing a few comet goldfish and fitted with a 75W-equivalent energy saver bulb in a conical shaped, metal clip on reflector. The reflector presses against the side of the tank, and the light remains on 24/7. I have three five gallon tanks situated along side the twenty. The whole set up is under a fluorescent shop light. Basically, I harvest daphnia every day, rotating the 5 gallon tanks so that each is harvested every third day. To harvest, I siphon the tanks from the bottom and strain through a fishnet, catching the flow through in a shallow plastic basin. I remove half the volume of the tank. The adult daphnia are collected in the net and fed to the fish. I then wipe down the sides and bottom of the tank with a potscrubber and replace the water with green water from the 20H tank. I then use a brine shrimp net to collect the small (baby) daphnia, and I return them to the 5gallon growing tank to mature. It is important to harvest regularly or the daphnia will bloom and then die off suddenly. Also, you must do partial water changes to the 20H green water tank often enough that the water stays light green and does not get too dark. So, you can see that this is possible, but way-too involved for most working folks. If I didn't have a job, I might be able to make this work, but for me, the brine shrimp are no problem. I have tried the yeast, powdered milk, and blood meal methods, but eventually, all of these lead to fouled water and dead cultures. The green water does not foul per se, and I have had the best luck with this method.

Best,

Rob

[Corrie]

"Moina will double every day in continuous culture"

Thanks Steve! That's what I needed to know.

"eggs had to come from a marine source"

John, it does not matter. The phospholipid profile of BBS is a mess. They are almost devoid of DHA.

"Am I right in thinking that the rotifers you produce/use are marine rotifers? "

There are no marine rots. Brackish is as good as it gets, with a high tolerance for full strength sea water.

"4 teaspoons of eggs cost more than a 1 lb tin of brine shrimp eggs"

Then you need a source for live cultures. Even rots from eggs take forever.

"I could/can not envisage daphnia cultures of sufficient size being reared in an artifical indoor environment."

I'm sure you have to have a University somewhere around you that is doing it.

"outside they can easily become contaminated"

That is exactly the same with rots. And most of that contamination is eating your rots and daphnia.

"in captivity" daphnia reproduce in "blooms"

There's no physical reason they would do that, so it would have to be some glitch in the way they are cultured.

"Can I please ask you to share your rotifer production techniques with us and if possible use the same techniques on daphnia to see how successful it is"

I'm game, but bear with me, I've never written it out before so I'll probably ramble all over the place.

[Corrie]

Rob

"I'm impressed that you have been raising clown fish."

LOL don't be, think of them as tilapia with a lot more salt in the water.

"you might be able to get enough daphnia by culturing in rotating stock tanks started with horse manure and green water."

euu
No thanks, I think I'll stick to algae paste.

"aquarium containing a few comet goldfish"

So you're feeding goldfish, to create waste to grow algae, to feed daphnia?

"If I didn't have a job, I might be able to make this work,"

This is my job, and I don't even have time to make that one work! :)

"It is important to harvest regularly or the daphnia will bloom and then die off suddenly"

Yep, that's called a culture crash.

"I have tried the yeast, powdered milk, and blood meal methods, but eventually, all of these lead to fouled water and dead cultures. The green water does not foul per se, and I have had the best luck with this method"

If you're using live algae, it can crash too.

[Corrie]

Steve, can monia be raised exclusively on algae?
Provided the algae has a decent profile?


I'm pretty sure they can, just need to check.

Corrie

[Corrie]

I guess not, since I can't even spell it right! LOL

Guys let me know if you really want to know how I've been culturing rots.
I'm not really up to typing it all out if no one is really interested.

Corrie

[Ranchu Rancher]

I went to BSD to look at there algae paste. They have four different ones. Is there one that is best for use with fresh water?

Gregg

[Corrie]

Gregg, I'm going to use nanno because I can freeze and re-freeze it. Nanno has a decent profile and grows rots just fine with nothing else.
Do not get one of the pastes that use glycerin as anti-freeze.
Also, these algae are cultured in salt water.
Thaw out what you need in a glass, slowly add fresh water over the course of a few hours. If you don't, the cells can rupture from the difference in osmotic pressure. Then keep that in the frig and use it as you need it.
You can use one of those old squirt plastic ketchup/mustard bottles.

Corrie

[Ranchu Rancher]

Thank You Corrie.

Gregg

[bekko]

can monia be raised exclusively on algae? They do best when raised exclusively on algae. In Hawaii we are not allowed to import the live cultures so everyone has been using Randy's Nannochloropsis. I suspect the Moina could feed more efficiently on the larger Isochrisis or Tetraselmis but you can't freeze these and the bottle would go bad before most people could use it.

-steve

[Corrie]

"They do best when raised exclusively on algae"

Thanks Steve

That's what I found out over the weekend.
One of my buddies is my "go to" on this stuff.
He's the head of the ag/aqua school at one of our universities.


As soon as I have time to slow down, I'll start another thread
on how I culture rots, and how I'm going to culture moina.
I would really appreciate it if you guys would help out, ask questions,
and make it as interactive as it can be.

I've been doing this by feel for so long, I'm not going to remember
everything on my own without help.

Corrie