In a hypothetical apnea contest between vertebrates, the killifish (Austrofundulus limnaeus) has routed the records of turtles and goldfish, able to remain in apnea "only" for a few days. Bazzecole, compared to this freshwater fish that is able to survive without oxygen for more than 60 days.
Jason Podrabsky of Portland State University (Oregon) has in fact tried to enclose some fish embryos in vacuum tubes: after 62 days, half of the larvae had survived. The exceptional resistance capacity of the fish derives, in reality, from adaptation needs: when the drought drains the seasonal lakes of Venezuela where the killifish lives, the larvae survive for a long time remaining buried in the mud, but here the activity of the bacteria exhausts all available oxygen supplies. What then is the secret of this unique apnea record? The killifish survivors, during the experiment, accumulated lactic acid (a by-product of metabolic activity in the absence of oxygen) very slowly, falling into a sort of hibernation that allowed them to slow down their metabolism considerably, so as not to damage the body. Understanding which gene is responsible for this slowdown could help to study the behavior of human tissues in situations where there is no oxygen, such as, for example, during a heart attack.