Mandarin Larval experiment with dry feed.

To cut a long story short, obtaining suitable copepods for raising Mandarins here in the UK has proven difficult. I have been trying to raise them for a month or two on rotifers without success and 7 DPH is my current best. I was about to quit and await an A Tonsa order which is due in April. I then saw that a supplier in the UK had started to stock Otohime feeds. I went ahead and ordered the smallest grade 75-150um and I started to experiment, it did not go to well.
While playing with ideas someone on a group page had mentioned GP feeds so I went ahead and ordered the smallest grade which was claimed 5-50um

So yesterday I fed 50 larvae the GP, I had lost them all 10 hours or so after feeding, and I suspect it was a pollution issue. I did however take some shots of the larvae before and after as I intend posting my findings in the UK forum once I have completed my trials.
 
4 DPH larvae before feed


 

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Sorry but the thread is only allowing one attachment at a time.
 

 
 
So that was the larvae before being fed.
 
 
 

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The Otohime and GP side by side under the scope.  Oto @ 75-150um  GP @ 5-50um
 
 

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About 10 hours later all the larvae were dead, I believe it was a pollution issue.
 
Dead larvae photo taken approx 10 hours after adding feed.
 

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They look full!... but dead.

-Adam

Yep they were all dead after 10 hours, but it appears they had been eating the dry food.

Very interesting!!  Thanks for sharing.  What is "GP food"?

Don't let fear and common sense stop you! =]

golden pearls I think they come from the us

Oh yeah.  Brine Shrimp Direct has the Golden Pearls.  My larvae love that stuff, but I was under the impression that it is not a complete feed, but more of an additive...?

Don't let fear and common sense stop you! =]

We're you using any ammonia control with these foods? This is an exciting project.

Since I can't get Otohime , I've been using a combination of Golden Pearls and Hikari First bites.  Both are designed as fry food, but largely for freshwater fish.

You use GP and first bites on mandarin larvae?

No, they are clowns.  But the First bites and GP replaced the TDO.

Sorry, yes the food is Golden Pearls.

The website I got the GP from stated Fresh and marine and shrimps. I also compared the make up of the Otohime and the GP and it is almost identical.

I usually use the chloramx, but failed to use it on this batch. These are trials, I do not expect immediate results as there is no protocol for raising Mandarins on anything other than live foods.

Both the Otohime and GP pollute small volumes of water quickly. Both have the appearance of rotifers when kept in suspension and my initial thoughts are all based on size. Those of you who have worked with Mandarins will know just how small they are.
Most successes with Mandarins have come with the use of copepods (A Tonsa) but smaller numbers have been raised on rotifers.

A Tonsa Nauplii average out at 70um
S Strain rotifers (which I have been using) 150-220 um
The Otohime I used   75-150um
Golden Pearls  5-50um

I am working on a way to keep the feed in suspension and to remove it. I will keep you all updated and will provide a link to my findings as they become available.
For now it is encouraging that Mandarin larvae may be prepared to take dry feeds and the picture above may be the first of a Mandarin with a full stomach fed on dry feed.

I collected a small spawn from my red pair last night (27-3) so I have a few days before I try again.

Have you thought about soaking the dry feed in a drop of something like selco, rinsing lightly and using that in suspension? Obviously it will not help with water quality but may just give you that extra edge when it comes time to push larvae through meta.

What are your thoughts on keeping it in suspension? I was thinking you could try raising the larvae in inverted 2L bottles with rigid airline dialed down to a bubble or two a second. That may be enough to continuously stir the powdered food.

A 2L bottle is a pretty small volume of water though, and if there are already pollution issues, that may only make it worse.  But maybe using inverted 2L bottle, with sections cut out and replaced with the appropriate sized mesh to allow for water exchange but to keep larvae in, and then clamp that onto the edge of something like a 20G long tank (the larger footprint would allow for more larval "flasks" on the perimeter).  The tank itself could have water filtration, small skimmer, that sort of thing....but the issue of getting uneaten food out would still exist

Removing uneaten food can be done by replacing the cap of the inverted bottle with a sheet of the mesh you mentioned earlier. Rubberband mesh over the 'top' of the bottle and insert a finer mesh window on one side, then you'll have a constant flow of water from the larger system that keeps food inside and suspended. To remove unbeaten food, simply turn off air flow for an hour and allow the food to style out through the bottle neck, add new food and return airflow. Then old food can be siphoned out of the main tank.


Think larval snagger with a twist.

I have a spray that is used for top dressing but I have not used it yet. I have ordered the parts to make a type of upweller although I may just simplify it and work on a flow through system.
The food stays in suspension fairly easily with just air, I have been running air at 1 BPS but both the Oto and GP do eventually settle.
I have mesh that will filter out 53um and above but the GP is 5-50um and so I plan on using a skimmer to remove it from the water in some kind of flow through. I have larger mesh's which will hold back larvae but allow food to exit.
If it does not work I have seen old RO units used with peristaltic pumps to filter water. At the moment it all remains a work in progress and there are plenty of options to explore.

To help with the pollution issue I have started building a flow through system, details posted here http://www.mbisite.org/Fo...1533&mpage=1#81533
I will report back with my findings.

Any news?

The next batch are ready to feed on Thursday night and another on Friday. I have had several spawns since the last trial but hatch rates and survival between Pro larvae to larvae stage have been too low to make it worth while. If I have enough larvae on Thursday I will run another trial and keep you updated.

Well I've finally got both of my pairs set up and in proper condition and spawning a started this week. I've not collected eggs yet as they are actually ahead of schedule and I wasn't expecting to be at this stage until August.

Naturally, I am completely unprepared in regards to live feeds. I'd like to back you up with this experiment until I have some cultures going. Do you think it's feasible to simulate what you've got going on? I hate to waste clutches of eggs until my cultures are going.

Thanks
Joe

Yes I only have a flow through that I built myself, the biggest problem with the dry feed is that it pollutes quickly. I think the key issues to resolve are keeping the food in suspension and water exchange. The feed does stay in suspension for a period of time but settles out. The GP settles slower than the Otohime (probably because of its smaller size)
I do not have anything to report back with the Mandarins yet as I am getting small numbers at day 4. Running the flow through for 5 or 6 larvae seems pointless. I also lost my red female but the spotteds continue to spawn almost nightly.
I had a nest of Onyx clowns that I had in the flow through from a hatch of around 80-100 I am down to 2 fish, but they have never seen a living organism and have been fed solely on Otohime A1, I skipped the GP with the clowns as they are able to take the larger food.

To what do you attribute the low mandarin hatch rates? Do you think it could be poor nutrition on the parents end resulting in low fertilization percentages or the fact that eggs aren't making it through the move into the system?

Also, which food are larvae showing a preference to? Are mandarin fry eating both oto and gp or do you think the gp is the only one worth buying?

I am not getting low hatch rates, its the period between   egg - prolarvae - larvae where I am losing them. I would be shocked if it were nutrition, it could be any number of factors and all I can do is change one thing at a time.

I would not say they show a preference, rather the GP is more suitable as it is 5-50 microns whereas the Oto is 75-150 micron. A Tonsa naups are around the 70 micron mark so it makes sense 70 micron or lower will work better. I would imagine that within a week or two of eating the GP they could just as easily take the Oto as they develop but thats guess work as I have not got that far. But I am sure it can be done after taking shots of Mandarins with full guts who have only been offered the dry feed.
I would say use the GP at least initially.

 what's new ..?
 
i aslo have 2cples of dragonets , and as you , they die at day 6/8..
i also try this king of food but i have to prepare it myself because there are no food like this in france (try to order on ebay today)
the constant water quality is also my problem, in 2 or 3 hours.... it's too late!!.
 
hatching results depend from broodstock feeding and from the male attentions , sometime this guys are too nervous too wait for the right moment ..because lady love to wait for egg issue .( sometimes i'm with 300 larvaes and i see them all die in a few hours  )
 
PS: (i'am a new member , from france (so sorry for my english) and did'nt find the member presentation post..where is it ? cause i hope could aslo help for this fishes)
derwins

GP staying in suspension longer the Otohime A1...
 
this is one of the selling point of GP... micro-encapsulation IIRC.  Otohime "S" is similar as it is marumerized, but not even within the micron size you are seeking.