Egg Development Journal

[CT_]

I was able to pick out a couple medaka eggs and this time they're in methylene blue so hopefully they won't cloud up and die.  I didn't take a photo at 1 day post fertilization but this one is at about the 2 dpf point.

At 1dpf, I could see the oil droplets coalesced into 2 drops (no photo). 

Today (day 2 pf) there's one obvious oil drop, a large yolk and embryo.

 

For reference, below is roughly 1 day(a) and 2 days(b) from an article taken with a much better microscope. 

[Hobbit]

Oooo definitely following!

[CT_]

I was going to do one a day but I can't help my self.  here's T=2.5dpf.  We have eyes now.  The eyes should get black pigment soon (withing hours if what I read was right).  Also the egg has been rolling around collecting more dirt.  They're covered in cilia to help them stick but they also collect dirt.

 

Edited August 19, 2021 by CT_

[Andy's Fish Den]

Very cool to see and watch as they develop

[CT_]

Weird, I thought I posted this morning but it didn't go through. Sorry if this gets posted twice.

Here's T=3 dpf.

Today I caught it on its lateral (side) view.  There's a little eye pigmentation now but they should look fully black soon (top photo).  There's also a heartbeat now too!  bottom photo (animated) between the eye and the oil spot.

 

 

EDIT: adding T=3.5.  eye pigments!

Edited August 20, 2021 by CT_

[Guppysnail]

That is so amazing! Thank you for sharing!

[Centraloregonaquatics]

This is amazing!! Thank you!

[Odd Duck]

On 8/19/2021 at 6:03 PM, CT_ said:

There's also a heartbeat now too!  bottom photo (animated) between the eye and the oil spot.

Awesome vid!  Love it!

[CT_]

T=4 dpf

A little bigger.  I saw it twitch in the egg but it wasn't frequent enough to catch on video. 

[Hobbit]

Ooooo!

[CT_]

T=5dpf

Lateral view.  I can see pupil and iris now!  Also this is a mostly closed container but somehow more dirt keeps accumulating. 

[Taco Playz]

This is so cool!

[Tami]

so cool -

 

[CT_]

T=6dpf, I think this is a ventral view with the tail wrapped almost all the way around obscuring the eye.  If I mess with the light too much the embryo will twitch and reposition inside the egg. 

I used two sets of tweezers to remove some of the fuzz of what ever is collecting on the egg and was able to get some better photos.

You can now see some of the vasculature around the yolk.  below is a drawing (taken from doi:10.1016/j.mod.2004.03.012) for reference so you know what to look for.

 

 

Edited August 22, 2021 by CT_

[CT_]

T=6.5dpf

I cleaned my microscope a bit, changed the water and detached this guy's sibling from dieing duckweed.  the sibling is a lot cleaner so I'm switching photoing it.

Turns out shallower water and a not terribly dirty microscope goes a long way for photo quality.

 

I took another video too (full video herehttps://streamable.com/v2g21s, quick gif below ).  you can see them twitch some too now and if you look really close you can see blood cells flow (the video compression unfortunately makes that a bit hard).

 

[Hobbit]

Woooow!!! That’s a great video!!

[eatyourpeas]

What an amazing thread! Thanks for sharing the wonders we can't see without magnification! 😍

[CT_]

honestly its making me want to buy another microscope...  I guess I know how I end up with so many gadgets now.

[CT_]

T=7.5 dpf

Not sure how these guys are supposed to last another 3 days in there.  they're getting pretty big for their eggs!

[CT_]

T=8.5dpf

I think they should hatch in about two days now. 

they're getting really long and are all curled up.  Also took another video since these guys are getting more wiggly by the day.  https://streamable.com/ag3to2

 

[CT_]

wellp.  I took those photos above at about 4pm today and then posted them after dinner.  I looked over about an hour ago(8pm) and all I saw was this:

Then I looked closer and saw this!

I guess either she had laid and held the eggs an extra day or its hotter than the 27-28C average I thought it was in here.

 

I guess I can test if they'll eat within hours of hatching now.  I've read conflicting things.

 

[Hobbit]

Ahh yay!!! Let me know when they start eating. I’m trying to breed ricefish as well.

[CT_]

they didn't take any of the food I offered today.  I found a journal article saying their yolk lasts 3 days past hatching and that they don't need food in that time period.  Its unclear to me when they'll take food though but I don't have to worry until Friday.

[ChemBob]

This is great! Thank you for documenting this. Its very interesting to see their development on the eggs, especially since I don't have the equipment to do so myself. I love this forum for the ability to share items like this with others!

[CT_]

Coming up on 48 hr.  Its really hard to see if they're eating but they're doing eating like twitching of their heads (but I don't see anything in their stomach).  The water is barely blue now so I'm going to add some moss after my next water change tonight and some green water in addition to the serra micron just so they have choices.  I also heard they develop better in sunlight (maybe a superstition though) so they're getting 12ish hrs of 10,000 lux (similar to a cloudy day, but feels super bright indoors) light.