How we prepare our eggs

[TyroneGenade]

Hello all

Here is some positive matter to digest today.

Here in the lab where I work we are spawning the Nothos over fine sand (fine as in it will go through a cake flour sieve). The sand is put into a shallow tray that isn't very deep. The fish have no trouble finding the way in and don't mind spawning in it. We harvest these sand tubs regularly.

The sand is sieved from the eggs. These eggs are then dumped onto a sheet of tinfoil (simply because) and then washed into a petri dish. From the petri dish the water is drained and the eggs flipped on to a layer of damp washed peat. The eggs are spread about so that they are not in contact with each other. The petri dish lid is then placed over the eggs and peat (the lid must not touch the eggs!) and the dish stored at about 25°C.

The eggs are checked daily for development and fungus. Fungussed eggs are removed with tweezers. The eggs are never touched by hand.

Using this technique the Notho eggs eye up in a very short space of time. We have 1 month old furzeri eggs starring us in the face. Likewise with black rachovii.

(Alas all the eggs are for research purposes as we can't distribute them at all.)

Hope the above was of some interest.

Regards

[stormhawk]

Tyrone,

I have a question. If fine sand is utilised as a breeding medium, wouldn't it be very messy in an enclosed system like a fish tank? Especially if the spawning pair thrashes about in the sand tub and loads of sand drop off into the surrounding area. I have this problem when I'm using coco-peat as a spawning medium.

[TyroneGenade]

The fine sand is far denser than peat and sinks very quickly. We see no undue sand spread over the tank. The fish can't spray the sand up when spawning like the peat which makes this method far less messy.

Given the colour of the sand it is also harder for the fish to find and consume their own eggs.

Cheerio

[erikthur]

I have at hand a special sand sized 0.2-1.0 mm in size.
Is it that kind of size or should it be smaller yet?

[TyroneGenade]

Hello

I would sieve the sand and only sue that which goes through the sieve for spawning.

Good luck!

[erikthur]

Now I tried to spawn my 2 pairs of N. foerschi with fine sand as the medium.
The sand grains are smooth and 0.2-0.6 mm in size.
The egg count was at least doubled compared to peat spawning and I found only a few eggs outside the spawning box compared to sometimes about 2/3rds when using peat. So the sand method is superior if one wants to know the egg count.

[RonWill]

Erik, your observation and feedback is encouraging. I've young trios of Simp sp. aff. stellatus “Urucuia” that are almost ready to spawn and want to try a 'cleaner' method.

Will later upload some pics of the 'Urucuia' that I took this morning. Their tub was filled with Sera filter peat media (small pellets) instead of peat moss. They checked out the tub but can't dive into it.

Tyrone, for peat divers, did the fine sand method work for you?

[TyroneGenade]

I haven't used the sand method on peat divers before... I don't think it will work as well but this is just a huntch. You can try and then let us know... ù

I know that while Simp. whitei and Aus. nigripinnis like to dive they will also plough like Nothos if the peat is shallow so they may well plough as a last resort with sand.

Another method is to use yarn mops instead of peat or sand. The fish will dive in to the mops and spawn and the eggs can then be harvested.

My suggestion is to put the eggs into peat or water incubate. We haven't had much luck with eggersi eggs on top of peat... they may be too small and sensitive compared to the big furzeri eggs.

tt4n

[RonWill]

Tyrone,
I've tried mop-in-bowl method, replacing peat, but since I hate fiddling with eggs I can't readily see, how am I going to incubate the eggs? I would hate to pick the eggs, one at a time.

Will a egg-laden drier/damp mop incubate the same? (ok... maybe a dip into thick peat tea before letting mop drip dry).

From my experience with GAR and AUS, I know that 'damp-mop-incubation' works. Stored in the dark for 10~14 days, the eggs will develop as in peat or water incubation. I normally see fry about 10 mins after wetting and most will hatch within the hour.

Of course, it may be a different story for annuals and their longer incubation period. Regardless, I'll spawn the Simp sp. aff. stellatus 'Urucuia' in sand and mop, and results will be updated in this thread.

[TyroneGenade]

With my whitei and bellottii I found I could simple "shake" the eggs out of the mop and then water incubate.

Hope that helps...

[RonWill]

With my whitei and bellottii I found I could simple "shake" the eggs out of the mop and then water incubate

Water incubate??? I've read (from you, I think) that Simp constanciae eggs can be water incubated too but frankly, doubt that very much.

I've a trio of CON, which spent almost a year in a permanent setup and have yet to see any fry or young CONs. These were the original batch from Kwek Leong and IIRC, received as eggs from Tony Terceira. [They were then known as Cynolebias constanciae but I guess you knew that :wink: ]

Was the water incubation of whitei and bellottii from personal experience? How long did it take for eggs to eye-up in your temp? Any particular issues I should note, regarding handling, water parameters or storage?

[TyroneGenade]

Water incubation takes about 3 to 6 weeks at about 25°C. The eggs won't just hatch but need to be stimulated to hatch with an increase of oxygen... I guess a BIG water change would do it.

Eggs that hatch out on their own tend to be week and don't fair so well. Eyed-up eggs seem to be able to wait a few weeks but then they hatch weak fry or die.

tt4n

[Joshua]

From the petri dish the water is drained and the eggs flipped on to a layer of damp washed peat.

Do you have to "bury" the eggs in the peat or can you just leave them on the surface of the peat?

[erikthur]

I also tried the sand method for one week with my Simp. suzarti.
The results were disappointing.
I could find very few eggs.
May-be because the fish are getting old (5 months).

I found 2 eggs in the sand box and 9 eggs outside the sand box.
Compare to N foerschi that laid almost completely all their eggs inside the sand box.

[TyroneGenade]

As I recall, the Simp. suzarti are peat divers so they probably did not like the sand. I don't think age is a problem. I was getting good spawns from my Simp. sp. South Bahia CI 99 when they were quite old.

And, no. I do not bury the eggs in the peat.

tt4n

[Svein]

Hi Erik
I think 5 months isn't too much getting a good breed. But sure, you have to use peat . I have use 5cm with peat, and this species give a lot of eggs!
Regards
Svein

[erikthur]

I can confirm that now - this week 55 eggs and that is counting only the eggs outside the peat container. Ie laid in the peat that spilled out because their spawning activities

[TyroneGenade]

Just a quick update:

For N. eggersi and rachovii the sand spawning seems to work well but the eggs seem to disentegrate on the peat if moved directly from the sand to the peat. Taking the sand spawned eggs and washing them directly into peat seems to work wonders at boosting egg survival. I believe the problem is mechanical damage in sorting the eggs on top of peat.

Also, using water from the tank of same temperature seems important at ensuing the eggs remain good. This may seem logical to some of you but it took us in the lab some time to figure out why all of a sudden the eggs were dying... The water in the tap was warm in summer but now it is winter and the water is cold. (Alas we don't have a "i'm freezing my 'nads off" smily.)

Erik, how are the foerschi eggs doing?

Regards

[erikthur]

I just checked the first spawn with the sand method from Oct. 26.
A fair number of the eggs seem fine so far (after 3 weeks).
Actually, sieving the eggs from the sand feels more traumatic to me than picking them carefully.

Addendum: I just spawn the fish in the sand. I incubate the eggs in traditional fashion in peat.