The last three males of an all-but-extinct fish species would really, really, really like to meet a female.

Once upon a time the Mangarahara cichlid (Ptychochromis insolitus) lived in a single habitat: a river in Madagascar from which the species gets its name. That river has now been dammed and the habitat has dried up. Today there are just three Mangarahara cichlids left—all males. Two reside at the Zoological Society of London's (ZSL) London Zoo Aquarium; the third lives at the Berlin Zoo.

Although the species appears to be extinct in the wild, ZSL London Zoo hopes that somewhere, somehow a female or two might exist in private hands. "We are urgently appealing to anyone who owns or knows someone who may own these critically endangered fish, which are silver in color with an orange-tipped tail, so that we can start a breeding program here at the zoo to bring them back from the brink of extinction," aquarium curator Brian Zimmerman said in a press release last week.

The zoo has already reached out to other facilities around the world, with no luck. Now the only hope lies in private aquarium owners, fish collectors and hobbyists who might see the zoo's appeal and realize that they own a female cichlid. The zoo has even set up a dedicated e-mail address for anyone with information: fishappeal@zsl.org.

Of course, even if a female does turn up, breeding won't be guaranteed. Zimmerman told the BBC News that the Berlin Zoo used to have a female that it had hoped to breed with its male. Instead, the male killed its potential mate. "It's a fairly common thing with cichlids," Zimmerman said.

Time may be of the essence: the two fish at London Zoo Aquarium are already 12 years old, and no one knows the lifespan of these little-studied, 5.5 centimeter fish. The Mangarahara cichlid was only identified as a new species back in 2006. Sadly, that may have been just in time for us to carve its name on its tombstone.

Photos: Zoological Society of London

Previously in Extinction Countdown: