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Intermittent streams account for approximately one half of the global river network, and are especially common in arid and semi-arid regions. These systems are inhabited by several fish species that are adapted to their natural flow intermittency. While many fish species rely on permanent pools or perennial reaches to survive during the dry season, our knowledge regarding fish survival strategies in dry reaches is incomplete. Our observations revealed that ammocoetes (i.e. lamprey larvae) of a non-parasitic brook lamprey (Lampetra sp.) survived in the hyporheic zone of an intermittent stream in the absence of surface water for at least 22 days. This is the first reported observation of ammocoetes persisting in the hyporheic water after loss of surface water, a behavior that has been previously reported for just a few fish species.