Researchers have discovered a new species of cavefish within a sinkhole in southwestern Madagascar. Shortly after swimming in the sinkhole's waters to find the fish, the scientists were afflicted with a "strange and debilitating" sickness dubbed "sinkhole fever," for which the species is named, according to the Guardian. The new species is Typhlerotris mararybe — "Mararybe" means "big sickness" in a local dialect.
The fish is small, with a length of about 1.5 inches (38 millimeters). Like many cavefish it lacks eyes and has "well-developed sensory canals and pores on its head," the Guardian reports.
Locals often visit this sinkhole and regard it as sacred, coming to offer prayers. While locals were familiar with several related cavefish species, they hadn't encountered this new animal, even though the people often descend to the sinkhole's waters via tree roots, reports the Guardian.
The fish is described in a study published in the journal American Museum Novitates.