- This topic has 4 replies, 3 voices, and was last updated 13 years, 5 months ago by
.
-
Posts
-
Hello,
I had problems with the sexes of the juvenile for a while. All of my juvenils where male. Than P. linkei breed in the winter and the summer. the sexes where 50:50 and I thought I had it, but it was just P.linkei.
I have now P. Langam only my own, only men; P. Sungai Bertam, one Pair and my own, only men and P.sumatranus one Pair and my own, where I am not sure whether they male or one female an one male. I tried to variate temperature and pH but nothing changed. The Sungai Bertam bred in pH 5.0-6.5 all of the juvenil were male, Langgam the same. P. sumatranus bred in pH 3.5-6.0 and I don´t know jet whether there is a difference. The temperature changed in the year (no heating) from 17-29°C.That do you think can help me or how do you handle it?
Bennie
Bennie, your report is very puzzling indeed. There seems to be no rule, except: The sex-ratio is not dependant from different water-values. But scientific experiments have shown: it is. Only on a statistical level, however.
So, my explanation for your puzzling experience is: your numbers are too low. If you breed extensively, only growing-up a few offspring, you will never reach a level of statistical relevance. Low pH or a high degree of humine material does not guarantee you only or many males, vice versa with females, it only increases the statistical probability of having males (vice versa for females). Maybe that your 50:50-success with linkei was due to the fact that this spawn was more numerous than others (which is often the case with linkei). Therefore, in case of intensive breeding the statistical forecast should be more secure than in the case of extensive bred small spawns. Here, the outcome may seemingly refute that statistics, but factually it doesn’t. It only shows that you did not reach the level of statistical significance.
Well, I am not sure. This is only my attempt to explain your puzzling experience.Now it´s clear. Both of the young P. sumatranus are male.
What should I do?
And you argument that the statistic is the point is possible, but I had 15 juvenile Langgam and 12 Sungai Bertam, 2 sumatranus; all male. That would me a big mess if it is only statistic.
And the P.linkei 5 male and 6 female was really a win in the lottery?
I can´t believe that.
I have linkei fry as well, and with 5 offsprings I have almost 50:50 (well, with 5 I guess it cant be 50:50 🙂 ) … but I have both females and males in this little group.
But I cant help thinking about that when I have bought paros in shops, quite often I get far too many males, – and maybe that could be because these fish have been bred somewhere and having the same problems as you.
At least two times have I bought at least 10-15 fish, and ending up with only one or two females..Bennie’s problem is one thing, the dominance of male fish in the pet shops another. In this case it is simply the result of the fact that male Parosphromenus are more attractive than females. The local catchers catch more males than females, already, because they are more attractive. The export companies sell more males than females for the same reason. More than once I saw tanks full of freshly imported Parosphromenus consisting nearly of males only, hundreds of fish. They do not bother thinking of such strange people as we are who try to breed the fish they sell. Aquarium fish are “ornamental fish”, fish to be kept as long as they live (or one is pleased by them), and then die. Then you buy new ones. Breeding is a pastime fitting with guppies or some barbs or labyrinths easy to be kept, not with Parosphromenus. We are exotic creatures trying to propagate them; for people with the intention of selling fish this is contra-productive. (Well, I exaggerate a bit …).
There is no such sexual onesidedness in nature. It’s the selection starting from the catch already and propagating itself through the tanks of exporter-importer-pet shop.
Bennie’s problem is different from that. I have to admit that I really don’t know the proper explanation.
- You must be logged in to reply to this topic.