early development

[koifishgirl]

Is that scales I am seeing on the little fry?

[JasonS]

Shouldn't be. From what I remember the scales don't start until 40 days or so.

Probably skeleton...

[koifishgirl]

When i take a good look at the photo I can see the skeleton of the koi but I swear it looks like scales. Im sure its not but it sure looks like it to me.

[MikeM]

Fascinating pics. Thanks for posting this series.

[ranskye]

i reckon so too, good pics,can you get one when its hatched out, they reckon they have a little attachment peice on the forehead that they use to stay attache dto something near where they hatch till theyre ready to break free and start looking for a feed. ive wondered if its a pad or if its just some sticky stuff.

[bekko]

Ranskye, thank you for the insights into spawning triggers. I read it quickly last night, but want to go back and digest it more.

As anticipated, there are some eggs with fungus today. I suspect that all the infertile and non-viable eggs (about 5%) have fungus. In addition, another 5% died over the last two days or just got fungus for no apparent reason. Anyway, 90% still look good. If it doesn't get too much worse before hatching, I will be very pleased. You do not need a microscope to pick out the fungused eggs as they look like large fuzz balls. I am not sure what the small dark spheres within the fungus mass are, but suspect they are packets of spored ready to burst and spread the the stuff to other eggs.



Here is a live one. The dark sphere near the perimeter at about 8:00 is the left eye. From there, the body wraps around the central yolk sack in a clockwise direction. The yolk sack is smaller today. It is going to have to last them for about 3-4 more days until they are ready to begin feeding. There is now a heart beat and fluid pulsing through the body. They are also much more active within the egg. I am not sure if they move around that much all the time or only become excited by the bright light from the microscope.



KFG, what you are seeing are not scales but the muscle. You know how a piece of cooked fish comes apart in flakes. This little chevrons in the egg are the flakes forming.

-steve

[ranskye]

great pics steve,
love ya work, the microscopic world is absolutley amazing.
ive seen the rounds on the ends of the fungus with my eyes before but i never thought it was spore sacs about to break and unleash some terror. makes sense as fungus produce spores..
still if youve got 90% your doing pretty well.
i think that even with spores floating around looking for something to attack, or even the initial attack of fungus being present that healthy eggs in good water and temperatures can fend for themselves. i mean if you had bad water i reckon the fungus could now go rank but to me it seems that the good fertilised egg has its immune system in place for it. it may be that the fungus takes hold as the wall deteriorates.
i still wonder if i really saw fungus attacking a living fertilised egg.
i spose it could happen if something went wrong halfway though.

if youve got that many still holding shape it shows that the mere presence of fungus doesent mean theyre doomed.
a dead egg has to be consumed by something.. in sterile conditions it will just melt away to nothing ( well oils and ammonia and all those things leading to more hardships in small volumes) but im pretty sure that in unsterile conditions large percentage of fungus eggs means somethings wrong and not only the unfertilised eggs are the problem. then sometimes it would be a poor fert rate.
this is why its so hard to understand it all and decipher what actually went wrong, a big process of elimination to solve it.

i know it take ssome work but im sure we all like to see more pics. eyeopeners...

is dick around?? can you tell us how they will spawn theyre fish in japan.
is it high tech or reliant on nature and numbers and volumes?

[bekko]

They started hatching last night and were about finished by the end of the day. Lost at least another 10% to fungus - maybe 15%. Not a big loss because it looks like I will have more fry than I have space and plankton for.

Since the spawning was 2-3 weeks later than anticipated, my plankton production is sort of screwed up. All but one of the small ponds (6-8 mt each) set up for a bloom at the end of last month were too old and had to be restarted. One that crached early had re-bloomed on its own and has a healthy population of rotifers. Luckily, a tosai pond had become really green and I had not taken the time to deal with it. So, every day I have been dumping an over-mature plankton pond, refilling with green water from the tosai pond, and innoculating with rotifers. It is going to be really close, but there might be enough rotifers to get the fry started when they begin feeding on Sunday (hopefully) or Monday. I will be innoculating a green water pond with Moina tomorrow in hopes that it will be ready towards the middle of next week when the fry are ready for something a bit larger.

Here is a fry photo:


This one is typical. You can see the beginnings of a stomach and intestine above the yolk sack. I am not positive about the thing that looks like a Happy Face just above the left gill, but suspect it is the beginnings of an otolith (earbone). Need a dorsal view to say for sure.

I haven't looked at a koi fry in about nine months, and it may be my imagination, but the yolk reserve looks really small. I hope it can last long enough to get them on solid food.

No pad on the head ranskye. I watched some in a beaker today and cannot figure out how they hold themselves in position, but they usually sit right-side up. Like you say, it may just be a sticky surface on the belly.

-steve

[ranskye]

yep steve they definatley seem to have a stickiness to them, when i see em in my spawn matting they are clinging and ill pull the net away and they swim until they can settle again. itd make sense for them to have it so they save energy and dont get swished away in a stream. i thought i read they had a sticky head pad but i certainly dont see a pad of such either.,maybe they do maybe not, in a beaker theyd have nothing to stick up to as they lay but come to think of it im sure ive never noticed them attached under the net strands..hmmm last time i noticed them clinging to a plastic tank lying head up tail down they were mostly all like that but i dont know which way round, i thought it was belly against the tank at the time but didnt look close.

ive got golden perch that float upside down with a very large egg reserve.

with koi, ive found they can go 3 days after hatch without a feed, i got worried too last time about them going hungry in a clear tank and let em go in a pond but they handled for 3 days first without feeding on much.
some species of fish will look like they handled but then die a few days after..
my old boss starts feeding day one but i dont think it neccessary as most arent interested, i dont think that they are developed to begin feeding on day one anyway. no functioning swim bladder and mouth parts opening up..

i think you said once youve got plankton or scoop nets, time before last i did what youd said and ran some green (actually a brown bloom) water- siphoned it from the broods into the fry tank for a few days and after that i used a pump on a different pond into a 100 so micron screen for a few hours and fed them that, think they were coppees, sorry copepods and it lasted in the fridge for 2-3 days then it went a bit too brown and i ditched it..
they grew well with that combined with some powder for up to about 6 days old. then i let em go into a copepod pond at about 6-8mm.
still easier and less work letting them into newly blooming pond.

ive got some goldies that are getting something that seems like sap on their skin, you know the white sheen that occurs, about 800 3 cm sanke type progeny in a recirc tank. most will survive though it seems like its making a few of them gill plates warp and recede a little.

kois dont seem to get it like that, the kois always seem a bit tougher and dont suffer a die out as easy..havent pin pointed why yet either.

[mervyn]

Hi

I have a Winchester compound binonocular microscope which I bought from Brunel Microscopes. They sold me an adaptor which screws into the lens thread of the camera and mounts on to one of the eyepiece tubes after pulling out the tube shaped eyepiece lens. Zoom in till the picture fills the monitor screen on the digital camera and snap...bobs your uncle. I took a snap tonight of a parasite and it came out very well. Would post the photo if I knew how!
MERVYN