Extinct Madagascar Swamp Fish Found to Be a New Species Living in an Aquarium

In the year 1994, researchers stumbled upon a small, isolated swamp along the coast of Madagascar. In this swamp, they encountered a mesmerizing multi-colored fish that swam just below the water's surface. The fish boasted a myriad of colors splashed across its scales, creating a stunning display when the light reflected off its iridescent form. However, as the water deepened, it became murky and dark.

A New Resident at the University of Michigan Museum of Zoology

After this remarkable encounter, the researchers collected the bright fish from the swamp and brought it to the University of Michigan Museum of Zoology, where it was placed in an aquarium. It lived there for years, nourished with algae, zooplankton, and larvae, thousands of miles away from its natural habitat. Despite numerous endeavors to induce reproduction artificially, the researchers were met with no success.

A Startling Revelation

When the fish disappeared from the wild after 1997, it was believed to have gone extinct. However, 30 years later, researchers from the American Museum of Natural History made a startling discovery. Upon closer examination of the preserved specimen, they found that the fish was, in fact, a new species that had been living in the aquarium all along.

Malagodon honahona: The Newly Discovered Extinct Species

The “new extinct species” was identified as Malagodon honahona, a member of the genus Malagodon. These small fish inhabited the "forested coastal swamps" on the eastern coast of Madagascar. The study revealed that Malagodons, including the newly discovered species, were declared extinct in the wild upon their discovery in 2023.

Distinctive Features of Malagodon honahona

Malagodon honahona, meaning “swamp” or “swampy” in the local Malagasy language, displayed an elongated body with an orangish-brown base color, a purplish-blue head, and a reddish-orange tail. The tail's rays were described as “spinelike,” and the fish possessed disproportionately “very large” eyes in relation to its body size. Additionally, the pelvic rays of the fish were noted to have small hooks at their ends, which developed further as the fish matured.

Possible Causes of Extinction

Despite extensive efforts, no additional specimens of M. honahona have been collected from the original locality or other potential habitats in the region. Consequently, the species is presumed to be extinct. The study authors suggested that the degradation of the coastal rainforest may have disrupted the water source that once sustained the small forested swamps, contributing to the demise of the species. Additionally, the introduction of an exotic species not native to Madagascar, potentially creating competition, was also considered a factor influencing the rapid extinction of M. honahona.