M. ocellatus (id2686)

Bestand seit (Halter ist der oben genannte Originalautor): 
20.11.2012
Anzahl: 
8.2 8 Males, 2 Females
Nachzuchtgeneration: 
0
Herkunft
Herkunftsart: 
Nachzucht
Haltungsbedingungen
Haltung: 
Teich (sommers)
Überwinterung: 
Kühl: unter 15°C
Ernährung: 
Fütterung, vorwiegend Lebendfutter
Brutansatz: 
Paarweise
Selektion: 
./.

The 10 unsexed fish, at 3,5-4cm were received about end November 2012. They were kept indoors in unheated aquarium, between 15-20*C, but rather at the lower end. Feed exclusively on Tubifex. They were subjected to a cooling down to 10*C in January for 2 weeks, but the temperatures gradually went up to 22*C indoors, before they went outdoors.
Fish went outdoors in April, when night temperatures remained around 10*C. They are kept mainly in round, 90l JOPA Moertelkuebel in pairs. When needed, further separations are made. Outdoors, they also receive some live mosquito larvae from time to time.

Until now, they showed little to zero fertility, 5 spawns resulting in only 7-8 larvae, from a single female (female 2). I tried to narrow the search of the affected animal, and I am almost convinced that the other female (female 1) is totally sterile. She (female 1) also exhibit a very weird behaviour. Not only the embraces are incomplete (maybe male's fault too? did he "felt" something wrong with the female?), but she keeps the light, spawning colouration even after finishing the spawn, for a while. During this time, she behaves very docile and unthreating, and her ondulating, submissive moves (like the approaching ones right before embrace/spawn episodes) soften the male's vigilence, and she proceed to eat a few eggs at a time, repeating the trick until her colour revert to normal- after that, the male is more careful and chase her away, but still not efficient enough to keep her to snatch a few more eggs.

I describe the spawning history here:

1. female 1 x male 1- incomplete embraces, zero larvae.
2. female 1 x male 1- idem. Now decided to try another male.
3. female 1 x male 2- idem.
4. female 2 x male 2- not observing well, but rather complete embraces; though, only 7-8 larvae as a result.
- meanwhile, female 2 affected by dropsy, so not yet trying with another male. Cured after 4 days with Furanol.
5. female 1 x male 2- total failure again.
6. female 1 x male 2- still waiting.

As you can see, the poor female 1 is a quite frequent layer.
Next plans:
- female 2 x male 3 (maybe the best-looking exemplar I have, largest and easy dominating male 2 when confronted for a few minutes trial).
- female 1 x another male
- female 1 x male 3

After that, I hope to conclude something more and find the best pairing in order to obtain my own stock.
First real winter for all fish (the much desired youngs and adults) will be cold, but not outdoors; I will let them hibernate in a foil-pond only after I will obtain enough animals. A very cold but frost-free attic, between 2-10*C will be the place. After first frosts, fish will be removed from the tubs to the attic, in their own water. Further water adding/exchanges will be made drop-by-drop, at a very slow rate, avoiding drastic changes in water chemistry when fish are letargic, since some say that it can be fatal. Even so, some say it's not, but I cannot yet test that.
..............................................................................

UPDATE 1.07.2013:
Yes, some eclosions finally occured. I took out the female after spawning on 29.06.2013, and let the male alone. Morning 30.06.2013 it started a 14 hours rain, that brought 125l/sqm. Quite a rain, during a bad drought. I decided to take the eggs in the house- anyway, they were very few left, about 15. Maybe the male ate the infertile ones? With some water, I transferred them in a small tank, and they started to hatch today. Some got fungus.

QUESTIONS:
I have the impression that female 1 eggs are a bit smaller than usual. What do you think about that?
Also, it seems that fertility may start to improve? And can I hope they will generally gain fertility after a long, cold hibernation? Is this partial sterility reversible?

During yesterday rain, after taking the remaining eggs, the water level rised fast in my tubs, and I went to check the fish, since I am always affraid of jumping fish. Yes, exactly the female 1 jumped!! She may have sat in rain (soft and acid, compared to my 20 GH and 7,5 pH water...) for a few hours. She looks very bad, but the permanent rain kept her alive. She was not able to keep balance for long, struggling to the surface for air... discolourations and stains, maybe some scratches... She is in 3 cm water, still balance-deficient, but has a good appetite. Hopefully she will recover.
.........................................................................................

UPDATE 2.07.2013:
None of those few hatched larvae survived. There is maybe something wrong with my batch of fish... Can a (maybe) too warm winter cause such a mess to their reproductive capacity? Until further opinions, I personally doubt.
The jumping female 1, their (not really) mother, seems to be better and recovering.

I am puzzled by the problems I have with this batch of fish... When I had the Yangzi form years ago, one single pair produced hundreds of healthy fry each spawn. And they were much less fed than these ones. But... lost ALL of them because of a single mistake. Just before I decided to give some to other people, to build back-ups and spread the fish in the hobby. And the pair was lost next summer to the nightmare Camallanus. End of Yangzi line, and also of M. ocellatus too in Romania. A very tough and rewarding line, but it seems that bad luck was tougher.
With these new ones, it's like I would try Betta macrostoma in 20GH water- but I suspect that the Brunei Jewels would be more productive than this line of Ocellati...
..............................................................................................

UPDATE

So, the 7-th spawn ( female 2 x male 3, on 29.06.2013) had good results in quality, considering the small fraction of recovered eggs. Maybe the male ate some of them, after being scattered by the rain.

After 2 weeks...
8- same female 2 x male 3 pair- about 800-1000 eggs, well fertilised as their previous spawn! At night, some lights in the house maybe disturbed the male, wich started to dislocate eggs and swallowed some of them during "rearranging" in the nest. To be on the safe side, removed the male, wich did a great job during the day, taking the eggs out of sunlight and moving them accordingly, to find the best spot for them. Maybe about 700 left? Hopefully.

This pair proved to be the best way to propagate them for the first year. The only good female (of only 2) and the best male. It worked and I will not change that now, considering the risk of failure if I will try another male, not to mention the exhaustion of the poor female. I will let them to spawn 2 more times, after 2-3 weeks interval between spawns, and then let the female getting stronger for winter.
To maximise the use of this reduced variability, some of their daughters will be paired next year with the other mature males I have. Anyway, inbreeding doesn't seem to affect most of ornamental fish, if the conditions are good- outdoors, sunlight, daily temperature swing, live food, various algae doing their detoxifying job etc.

Water-spitting behaviour of the male 3: I firstly noticed this archer-fish (Toxotes sp.) behaviour when I was getting closer to the nest, trying to observe. I thought it was some defense/intimidation behaviour, but I can't figure out why and against what type of threat did it evolved for. Maybe from the same reason as Toxotes did- hunting? Hitting small invertebrates and bringing them down in the water?
Bad filming skills, dirty glass and greenish water, but here it is: http://www.youtube.com/watch?v=J1YF7Oli8Eo

Kommentare

Great video, Fabian!

Not caused by the filming skills, Smile.
But what you documented in this film ist realy great: This spiting behaviour!
I never saw this, maybe because i did not film and so overlooked it ...
Maybe he is spiting to swirl the eggs at this place to better find and collect them?

Actually my time is a bit rare - I think you did notice this allready as I'm actually quite in the virtual world (my site and emails) ...
But at weekend i'll try to answer all the outstandings and i think i will also make a translation into german of your stock-entry and it's great oberservation notices.

Thanks again for this great observations.

Tschüss
Erich

PS:
By the way, if you have problems to understand any of my observation notices which seems interesting to you, give me a sign and i'll make a translation into english.
And I added the language Română to the site, so you possibly feel more comfortable here.

News on low fertility issue

Thanks, Erich!

Still a bit difficult to manage the infos here, but it will work, eventually.

The spitting was totally separate of the egg-manipulation process. The male was always in open water areas, no eggs in proximity. It was a hot day, and I never observed the spitting during other spawns. He moved repeatedly all the eggs in a shady area when sun directly hit the initial one, and finally moved them back when sun was gone- quite an interesting procedure to observe. Moving to shade was effected in 2 steps, and the returning also in 2 steps, not directly!
I was not home for a week after eclosion, so the larvae from that spawn were left on their own, in an outdoor 90l mortar tub, filled only with 65 l. Returned home, I noticed a sharp decrease in their numbers, and quite a few of the smaller ones floating dead at the surface, and some trying to go deep, but floating back to the surface. Cannot get why, but later I saw a bigger one trying to swallow a tiny one, giving up eventually, but the tiny one being condemned. So, bladder/flotation issues, next to immediate death, seemed now to have an explanation. They were more likely attacked due to hunger, since deaths stopped right after I started feeding them again. Quite a selection, I would say...

As for the adults, I am quite sure now that I may be having kept them too warm, as the most plausible reason for their low fertility. It got better with time, especially for the females. Even the female 1 produced about 400 eggs- not much compared to female 2, and less frequent too, but an improvement is obvious.
The males seem to recover more slowly since the pairing of male 1 with the female 2 (the fertile and frequent spawner) resulted in about 10% not fertilised eggs. Not much larvae in the final, but that was my fault: I allowed Cyclops in that tank, quite a lot of them, and only after being left with about 50 (!) fry, I found that they may attack even larger larvae. That had not much of a selection value in my opinion, just thinning their numbers, unfortunately. From now on, Cyclops are banned from breeding tanks.

Well, hopefully the next winter will reset their endocrine system and get best results from all my stock. Therefore, it is (almost) confirmed again that species/ecotypes subjected to cold winter conditions in the wild may have fertility problems when kept too warm during winter, or not being subjected to a true hibernation. That was observed in M. ocellatus by others too, along with immunity deficiencies. I said "almost" since it will be fully confirmed if their fertility will be noticeable increased after a cold winter. But still, even without that change, the truth may be the same, since there is the probability that once affected by warm overwintering, an animal will not necessarily revert to his normal fertility after offering them a cold winter, the first missed cycle having definitive consequences.

Anyway, I am satisfied that I obtained enough youngs to form a base of Romanian-born fish, as we all know that they will be much better adapted to their local conditions compared to the parents. I will even afford some for outdoor winter test too, and the bulk will hibernate in controlled conditions.

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