Then the first fish starts to blow, spitting jets of water toward the crater, whirling up sand and revealing the worm that lies hidden underneath. Breams are incapable of harming the sand striker, as delicate fins and even the most forceful water jet can’t pierce an exoskeleton. But what they can do is expose and warn. Their spurting alerts others nearby to the worm’s stealthy presence in a kind of effervescent whisper network.