hybridisation?

[VAN BESIEN Hugues]

Hi,

We try “theoretically” to prevent hybridisation and to keep our fishes as “pure” forms?
But do hybridisation occur really in the nature or in tanks?
What are the issue (sterile fishes?) for parosphronemus
Or do fine differences between our species make that breeding between two forms don’t come?
Different colors by the males? differences in the breeding “dance”, differences beetween females which we cannot see?
Has someone even tried to make controlled cross-breeding?
Hugues

[Martin Fischer]

Hi Hugues,

I’m not experienced at crossbreeding Paros, but I assume that hybridization of closely related species (e.g. the Harveyi-Group) is of course possible, and perhaps also happening in nature, where different species get in contact at some sort of borderline. I get to this point, because especially the members of this group don’t only show similarities in colour-patterns, but also in courtship behaviour and mood-related colouration… So why shouldn’t it be possible. As far as I remember, someone from the IGL-Forum has already bred hybrids accidently a few years ago. But it could also have been somewhere else…

These crossbreeding experiments that you talk of, could be interesting to confirm the status of some species, but the problem is: of course, classically, hybrids between two species should show decreased fertility or even be sterile, but I’m not so sure if this also applies to fish, especially closely related Paro species that vary only slightly in small colouration details. I think they could produce fertile offspring, why not?
Problems with fertility could also occur some generations later, so it would take very long to get results and it would furthermore not be clear if the infertility is a result of the cross- or the in-breeding afterwards.

So, since I don’t even have enough tanks for all the different species and forms I’d like to breed, I’ve not started such experiments yet 😆 .

Martin

[Peter Finke]

The questions of Hugues are to be taken very serious. I could confirm everything that Martin-EF has replied to him.
1. There have been some crossbreeding-attempts under strict control, but they have not been undertaken systematically (say in the case of a few species only) nor long enough (say comprising several generations). Therefore we do not know anything for sure.
2. It is highly probable (but not definitely confirmed) that some crossbreeding has been undertaken unconsciously by aquarists because of the difficulties of identification of the species and especially the females.
3. One even cannot exclude that there has been “natural” crossbreeding; in fact some species may have been the result of crossbreeding of their ancestor-forms. For the most cases of the present-day distribution however we could exclude that by the fact that a certain home range is in most cases inhabited by one species only. There are only verx few examples of sympatric occurrence of two species (see our species accounts). In each case the two are very different indeed and they inhabit different strata or niches of the same habitat.
4. We must be patient until we get further knowledge on the genetic relations of our fish. Actually the Fish-BOL-group in Canada has finished their investigations (Dr. Dirk Steinke) and will tell uns soon about the findings. Another genetic researcher (Dr. Lukas Rüber) in Bern (Switzerland) will take over and complete that research by further investigations with different methods. Both scientists are members of the Parosphromenus-Project.
5. Until we have better knowledge it is a good maxime to behave very cautiously as a keeper and breeder of that fish. As Martin-EF has pointed out the rather similar species of the harveyi- or bintan-group should never inhabit the same tank, at least not for breeding purposes. It would be quite irresponsible to do that and raise possible offspring and distribute it to other friends. Until we do not have better knowledge this behaviour might lead to mixed forms with a reduced fertility. We only can hope that some experience with licorice that will not readily spawn is not due to such a history of their parents …

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