Fish Use ... Sign Language? At least two kinds gesture while hunting prey, study suggests By John Johnson, Newser Staff Posted Apr 30, 2013 1:57 PM CDT 12 comments Comments Groupers help their hunting pals through sign language of sorts, a new study says. (Shutterstock) (Newser) – Fish might have more going on in their fishy brains than thought, a new study suggests. Researchers found that at least two types—groupers and coral trout—use what amounts to sign language to help their hunting partners, reports LiveScience. The finding plays off another unusual trait: Both fish are known to team up with other creatures, coral trout with octupuses and groupers with moray eels, to hunt prey. Let's say an octopus is in hot pursuit of potential dinner, but the prey escapes into a hiding spot. At that point, the coral trout goes over to said hiding spot and does a sort of headstand and shake, with its head facing the prize. The octopus ferrets out the prey, and the chase is back on. (Groupers do something similar with their hunting pals.) We'd like to say that a successful hunt ends with the two creatures sharing a meal, but, alas, "dinner goes to whichever sea creature snags the prey first," notes PopSci.