XNP project annual report – year 5

After five years of the project's existence, we can look back on our experience a little more and evaluate how successful this format is. In short: it works! We cannot prevent the loss of some fish. Or many fish, there are differences of hundreds of individuals from year to year. But it's great to see the map of breeders who are intensively dedicated to northern platyfish expanding and thickening. We got these species into several European countries where five years ago they were not kept at all - now there are hundreds of them and the number of breeders is increasing. Anyone interested in X. meyeri or X. couchianus can obtain them and join the project. Sometimes they have to wait a bit when the distances are too big, but we have these species and maintain them in safe numbers. Both species are extinct in the wild and we know that we can rely on our project to "look after" them.

The basic principles of conservation breeding managed in this way are proving themselves. The help of the coordinator with fish transfers is useful; if necessary, you can easily get in touch with a breeder who has surplus. Communication at least regarding the annual census is absolutely necessary, it is from the feedback of individual aquarists that we can put together a picture of the growing population and thus be sure that "there are enough northern platyfish".



Here are the numbers of fishes kept and how they evolve since the start of our project (as of the beginning of 2019, 2020, 2021, 2022 and 2023, respectively):

Xiphophorus meyeri Spotted:            434 - 645 - 1145 - 1436 - 1072

Xiphophorus meyeri Wild Type:        93 - 180 - 109 - 37 - 210

Xiphophorus couchianus:                  114 - 180 - 438 - 664 - 765

Xiphophorus gordoni:                        29 - 63 - 56 – 18 - 27

Xiphophorus sp. "Apodaca":             12 - 0 - 0 – 0 - 0

Xiphophorus sp. "Regio":                  19 - 110 - 83 – 86 - 49

Total number of fish:                         701 - 1178 - 1831 - 2241 - 2123

A greater decrease in individuals occurred in the basic form of X. meyeri, it was caused by the fact that several breeders lost all or most of their fish. But new breeders were added, so that compared to 26 in 2021, there were even 28 at the end of 2022. We succeeded with X. meyeri Wild Type (the form without spots), where we created another functional and very productive group. For X. gordoni the numbers look like going up again, but vast majority (25 individuals) of those fish form one completely new group. Hopefully the breeding will be successful. X. sp. "Regio" has seen a big drop in individuals due to us losing (see below) the member who kept most of these fish. But further development is promising, the remaining fish are reproducing.



Compared to last year, which we concluded with 42 members, at the end of 2022 we were again much more: 51. However, as part of the annual census, we came to the conclusion with several aquarists that their further participation is unnecessary - they do not keep any northern platyfish. This is not a decisive criterion for participation in the project, but if these people are not interested in communicating and continue to devote themselves to northern platyfish, we have agreed to terminate their membership. However, this decrease will only be felt in the following year.

The new members are from the Czech Republic (including two employees of the Ostrava Zoo who participate as private breeders, and also the Pilsen Zoo), Poland (the first ever breeder from this country), France, Austria, Germany, Hungary and Great Britain (Zoo Tropiquaria).



The first profile of the species (X. meyeri) and the first profile of the biotope (Múzquiz, locality of X. meyeri) with detailed data and photos were published on the website of the Xiphophorus Working Group (https://xipho.org/). We want to continue making similar information available to the general public.

The XNP project was also presented at an international meeting of aquarists in Thannhausen, Germany in August 2022, which was dedicated to conservation breeding. The video of the lecture (in German) is available here: https://www.youtube.com/watch?v=Tx2xBQOqrbM



Two significant events occurred within the project as a whole. First we were for the very first time forced to expel a member for selling fish. Instead of offering them to other members of the project to help keep them in the group of people who work together, he sold them outside the project. This is a gross violation of the rules, made even worse by the fact that it was X. sp. "Regio" – this fish may already be extinct in the wild, so each individual is very valuable. At the same time, it can easily be confused with other platyfish, so the reliability of the source from which we get the fish is key - fish outside the project are not trustworthy and from this point of view are "lost" unless we back-check their genetics. How much easier it is to breed them and share them among people who cooperate and know each other... Violation of the rules and selling fish behind others' backs unfortunately casts a bad light on the project and can damage the reputation of private breeders, but we believe that by decisively solving it in accordance with the rules, we have done the maximum to repair damages.

Secondly, representatives of Zoo Ostrava and Aquarium tropical Paris (both institutions are members of the XNP project) received a grant from the European Union of Aquarium Curators, thanks to which they can start cooperation with a new Mexican partner, the Universidad Autónoma de Nuevo León (UANL) next year. Of course, it will mainly be about northern platyfish!

There is no change in the financial status, i.e. all costs were covered by the respective members individually and the balance of the project is zero.


Plans for the future

In 2023, we will make significant progress in the aforementioned cooperation with UANL directly in Mexico. We will work with students and university staff throughout the year. Part of this cooperation is also a visit to the localities of all northern plats (and also X. sp. "Regio"), researching the possibility of reintroducing some species in the future and, last but not least, taking the first steps to return X. meyeri to their homeland, at least for the time being in conservation breeding in aquariums (this species is not kept in Mexico at all). The fish we have together in the XNP project are, of course, a necessary prerequisite for us to be able to even think about something like this.

In addition, samples are being collected for Mycobacteria research in both species extinct in the wild (X. meyeri and X. couchianus). We hope that we will succeed in breeding X. gordoni. We would also like to increase the number of individuals (and breeders) of other less represented fish: the spotless form of X. meyeri and X. sp. "Regio".


In conclusion, as I do every year, I would like to thank all the members of the XNP project once again. You are protecting rare species from extinction!


Markéta Rejlková

24.5.2023, Ostrava, Czech Republic