A very good question, Eric. And I think the answer is yes, the fish will show signs of abnormality when there's too much inbreeding. But that will lead us to the next question which is,Originally Posted by woodduck
"Why is it that the problem of inbreeding does not happen to killifish like Nothobranchius which live in ponds where no (or very few) new genes are ever introduced?"
I don't know if my answer to this question is correct as it's just my own theory but I believe the problem of inbreeding can be overcomed if the selection process is very rigorous. In nature, the Nothos live in ponds where the same group of fish has been there for thousands or maybe millions of years. Other than the fact that occasionally, an elephant which has been bathing in another pond may bring a new egg along with the mud that is stuck to its feet, no new genes are ever introduced.
In nature, there's this process called natural selection where only the strongest males get to fertilise the eggs. Males fight amongst themselves for the chance to mate with the females so only the strongest genes are passed on to the next generation. In such a scenario, inbreeding isn't a problem.
In our tanks, the process is artificial selection and we the breeders are the ones doing the selecting. Usually, we pick what we think is the best male to mate with the females. We tend to equate "best" with "most colourful" which may not necessarily be the way Mother Nature would choose.
But we can simulate the same conditions as nature in our tanks by having many males and females in one tank. I call this the "orgy" method. However, unlike a human orgy, a fish orgy allows only one male to do the mating :wink: and he's the Alpha male. I have my Notho guentheries all in the same tank but there's only one breeding bowl inside. And from what I've observed, only the Alpha male gets to use the bowl so although we can never emulate the conditions in nature completely, we can have a more rigorous selection process in our tanks if we let the fish decide for themselves which is the best one among them to carry the genes forward.
Here's a pic of 3 males facing off each other for the right to go into the bowl. The females are in the background waiting for the outcome of the face-off. You see this quite often in WWF wrestling too
Loh K L
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