A primitive Australian fish living in a San Francisco museum is believed to be the oldest living aquarium fish in the world. Methuselah is a four-foot-long (1.2-meter) Australian lungfish, weighing around 40lb (18.1kg). The species has both lungs and gills and is believed to be the evolutionary link between fish and amphibians. The lungfish was brought to the San Francisco museum in 1938 from Australia and now lives at the California Academy of Sciences. The species is threatened and can no longer be exported from Australian waters so biologists at the academy say it’s unlikely they’ll get a replacement once Methuselah passes away
