Unfit for Survival?

There are species of animals that are very endangered, so much so that they are really on the edge of becoming extinct. One such species is the sweet water fish Mangarahara cichlid from a river in Madagascar. It is believed to be extinct in the wild, due to dams constructed by humans, making their natural habitats dry. Three fishes are known to be alive, all of them males. Female fishes of this species are therefore sought after. The hope is that some private fish collectors have at least one female, which might be the basis of reconstructing the species.

There are, however, dangers. The last known female to be alive was put together with the male living in a zoo in Germany, but instead of mating with her, he killed her. I figure this may show that not all species are fit for survival. Sure, it might have been this particular male that was mentally ill, but if one of only a handful of individuals remaining of a species is crazy, how can you reconstruct the species without keeping that mental illness in the genetic lines?

I say this fish species looks unfit for survival, so maybe it should not survive. I hope I am wrong, though. It would be a happier ending of the story, if the species is reconstructed.